This document provides a summary of key functions and commands for importing, managing, manipulating, and analyzing data in R. It covers topics such as importing and exporting data, data types, subsetting data, merging datasets, creating and sampling random data, summary statistics, and transforming data. The document is intended as a cheat sheet for common data management tasks in R.
Desk reference for data wrangling, analysis, visualization, and programming in Stata. Co-authored with Tim Essam(@StataRGIS, linkedin.com/in/timessam). See all cheat sheets at http://bit.ly/statacheatsheets. Updated 2016/06/03
Grouped data frames allow dplyr functions to manipulate each group separately. The group_by() function creates a grouped data frame, while ungroup() removes grouping. Summarise() applies summary functions to columns to create a new table, such as mean() or count(). Join functions combine tables by matching values. Left, right, inner, and full joins retain different combinations of values from the tables.
The document discusses importing and exporting data in R. It describes how to import data from CSV, TXT, and Excel files using functions like read.table(), read.csv(), and read_excel(). It also describes how to export data to CSV, TXT, and Excel file formats using write functions. The document also demonstrates how to check the structure and dimensions of data, modify variable names, derive new variables, and recode categorical variables in R.
Stata cheat sheet: programming. Co-authored with Tim Essam (linkedin.com/in/timessam). See all cheat sheets at http://bit.ly/statacheatsheets. Updated 2016/06/04
As part of the GSP’s capacity development and improvement programme, FAO/GSP have organised a one week training in Izmir, Turkey. The main goal of the training was to increase the capacity of Turkey on digital soil mapping, new approaches on data collection, data processing and modelling of soil organic carbon. This 5 day training is titled ‘’Training on Digital Soil Organic Carbon Mapping’’ was held in IARTC - International Agricultural Research and Education Center in Menemen, Izmir on 20-25 August, 2017.
This document discusses various data types and structures in R. It begins by defining data types as categories of values like numeric and character. Data structures are described as how data is stored, such as vectors, factors, matrices, data frames, and lists. Examples are provided for each structure showing how to create them and access their elements. The document concludes by demonstrating how to work with built-in datasets in R, including viewing, summarizing, and accessing their columns and rows.
This document provides an overview of various data structures in R including vectors, lists, factors, matrices, and data frames. It discusses how to create, subset, and coerce between these structures. It also covers handling missing data and common data type conversions. The document recommends several books and online resources for learning more about R programming and statistics.
R can be used to summarize and visualize data in various ways. Descriptive statistics like mean, median, range can summarize a single variable. Correlation and regression can show relationships between two variables. Frequency tables and cross tabs show counts and proportions of variables. Graphs like bar plots, histograms, boxplots and more can visualize one or more variables. Pie charts, scatter plots and heat maps are other options. R has functions for each of these techniques to explore and communicate patterns in data.
Desk reference for data wrangling, analysis, visualization, and programming in Stata. Co-authored with Tim Essam(@StataRGIS, linkedin.com/in/timessam). See all cheat sheets at http://bit.ly/statacheatsheets. Updated 2016/06/03
Grouped data frames allow dplyr functions to manipulate each group separately. The group_by() function creates a grouped data frame, while ungroup() removes grouping. Summarise() applies summary functions to columns to create a new table, such as mean() or count(). Join functions combine tables by matching values. Left, right, inner, and full joins retain different combinations of values from the tables.
The document discusses importing and exporting data in R. It describes how to import data from CSV, TXT, and Excel files using functions like read.table(), read.csv(), and read_excel(). It also describes how to export data to CSV, TXT, and Excel file formats using write functions. The document also demonstrates how to check the structure and dimensions of data, modify variable names, derive new variables, and recode categorical variables in R.
Stata cheat sheet: programming. Co-authored with Tim Essam (linkedin.com/in/timessam). See all cheat sheets at http://bit.ly/statacheatsheets. Updated 2016/06/04
As part of the GSP’s capacity development and improvement programme, FAO/GSP have organised a one week training in Izmir, Turkey. The main goal of the training was to increase the capacity of Turkey on digital soil mapping, new approaches on data collection, data processing and modelling of soil organic carbon. This 5 day training is titled ‘’Training on Digital Soil Organic Carbon Mapping’’ was held in IARTC - International Agricultural Research and Education Center in Menemen, Izmir on 20-25 August, 2017.
This document discusses various data types and structures in R. It begins by defining data types as categories of values like numeric and character. Data structures are described as how data is stored, such as vectors, factors, matrices, data frames, and lists. Examples are provided for each structure showing how to create them and access their elements. The document concludes by demonstrating how to work with built-in datasets in R, including viewing, summarizing, and accessing their columns and rows.
This document provides an overview of various data structures in R including vectors, lists, factors, matrices, and data frames. It discusses how to create, subset, and coerce between these structures. It also covers handling missing data and common data type conversions. The document recommends several books and online resources for learning more about R programming and statistics.
R can be used to summarize and visualize data in various ways. Descriptive statistics like mean, median, range can summarize a single variable. Correlation and regression can show relationships between two variables. Frequency tables and cross tabs show counts and proportions of variables. Graphs like bar plots, histograms, boxplots and more can visualize one or more variables. Pie charts, scatter plots and heat maps are other options. R has functions for each of these techniques to explore and communicate patterns in data.
This document provides an overview of topics that will be covered in a two-day statistical programming course in R, including:
1. Vector and matrix operations, file input/output, and probability density functions.
2. Distributions like binomial, Poisson, normal and uniform as well as hypothesis testing using t, z, F, and chi-square.
3. Linear and multiple regression techniques, including prediction, residual analysis and modeling.
Case studies and examples are provided for many of these statistical techniques in R, such as linear regression, hypothesis testing, and probability distributions.
This document provides a summary of functions for input and output, data creation and manipulation, indexing, and getting help in R. Key functions covered include read.table() and read.csv() for reading data, c(), seq(), and rep() for data creation, [ and [[ for indexing vectors, lists and data frames, and help(), ? and apropos() for getting help documentation in R.
This document provides an overview of essential data wrangling tasks in R, including importing, exploring, indexing/subsetting, reshaping, merging, aggregating, and repeating/looping data. It discusses functions for reading different file types like CSV, Excel, and plain text. It also covers exploring data structure and summary statistics, subsetting vectors, data frames and matrices, reshaping between wide and long format, performing different types of joins to merge data, and using loops and sequences to repeat operations.
This document provides an overview of descriptive statistics and data visualization techniques using Python. It first describes summarizing a dataset using measures of central tendency, variation, skewness, and kurtosis. These include calculating the mean, median, mode, standard deviation, variance, and coefficient of variation. It then demonstrates bivariate analysis through scatter plots, correlation coefficients, and regression lines. Finally, it shows various data visualization graphs that can be created like bar charts, stacked and percentage bar charts, line and pie charts, box plots, histograms, stem-and-leaf plots, and heat maps using libraries like Pandas, Matplotlib and Seaborn.
This document provides a brief introduction to basic R features such as starting R, entering commands, importing and manipulating data, creating vectors and data frames, and performing summary statistics and visualizations. Key points covered include starting R, entering commands and comments, arithmetic operations, creating sequences and assigning objects, importing data from files, subsetting and manipulating vectors and data frames, and creating histograms, boxplots and other plots. Examples are provided using the built-in FlightDelays data set.
This presentation provides a brief introduction to data types and objects in R. I've not covered 'array' in the presentation, which is a multi-dimensional object [More general than matrix].
This document provides examples of different R data structures including vectors, matrices, lists, and data frames. Vectors are one-dimensional arrays that can contain only one data type. Matrices are two-dimensional arrays that can contain only one data type. Lists are collections of elements that can contain different data types. Data frames are two-dimensional structures similar to tables or spreadsheets that can contain different data types across rows and columns. The document demonstrates how to create, subset, and manipulate each of these structures through examples.
This document discusses various methods for importing, exporting, and summarizing data in Python using the Pandas library. It covers reading and writing CSV, TXT, and XLSX files with Pandas, checking the structure and dimensions of data frames, handling missing values, and modifying data through functions like rename(). The key methods described are read_csv(), read_table(), read_excel(), to_csv(), info(), isnull(), sum(), head(), tail(), and describe().
The document outlines various statistical and data analysis techniques that can be performed in R including importing data, data visualization, correlation and regression, and provides code examples for functions to conduct t-tests, ANOVA, PCA, clustering, time series analysis, and producing publication-quality output. It also reviews basic R syntax and functions for computing summary statistics, transforming data, and performing vector and matrix operations.
This document provides a summary of common functions and operations in R for input/output, data manipulation, indexing vectors and lists, and converting between data types. Key functions covered include print(), format(), write.table(), read.table(), c(), rep(), seq(), and data.frame() for creating and manipulating data. Indexing techniques allow extracting or replacing elements of vectors, matrices, data frames, and lists. Functions like str(), summary(), and dim() provide information about R objects.
RStudio is a trademark of RStudio, PBC. This document provides a cheat sheet on tidying data with the tidyr package in R. It defines tidy data as having each variable in its own column and each observation in its own row. It discusses tibbles as an enhanced data frame format and provides functions for constructing, subsetting, and printing tibbles. It also covers reshaping data through pivoting, handling missing values, expanding and completing data, and working with nested data through nesting, unnesting, and applying functions to list columns.
A short list of the most useful R commands
reference: http://www.personality-project.org/r/r.commands.html
R programı ile ilgilenen veya yeni öğrenmeye başlayan herkes için hazırlanmıştır.
- R is a free software environment for statistical computing and graphics. It has an active user community and supports graphical capabilities.
- R can import and export data, perform data manipulation and summaries. It provides various plotting functions and control structures to control program flow.
- Debugging tools in R include traceback, debug, browser and trace which help identify and fix issues in functions.
R can be used to analyze data and perform statistical analysis. Functions like help(), ? and help.start() provide information about other functions. Objects created in R sessions are stored by name and can be removed with rm(). Vectors like x=c(1,2,3,4,5) can be created and their length checked with length(x). Subsets of vectors can be selected using logical or integer indexes inside square brackets. Matrices are multi-dimensional generalizations of vectors that can be manipulated using operators like * and %. Data can be read into R from external files using functions like read.table() and read.delim(). Common statistical distributions like normal, uniform and exponential are available as functions in R for
R can be used to analyze data and perform statistical analysis. Key functions include help() and ? to get information on functions, and objects() to view stored objects. Vectors can be created with c() and manipulated using arithmetic operators. Matrices are two-dimensional arrays that can be operated on using *, /, and t(). Larger datasets are typically read from external files using read.table() or read.delim(). Common distributions can be explored using functions like dnorm(), pnorm(), and rnorm(). Statistical analysis includes commands like cov() and cor() to measure covariance and correlation between variables.
This document provides an introduction to manipulating tables in MySQL, including how to alter tables by adding, dropping, and modifying columns, how to insert and import data into tables from files using commands like INSERT, REPLACE, LOAD DATA INFILE and the mysqlimport utility, and how to perform updates and queries on table data using commands like UPDATE and SELECT. Examples are given for each task to demonstrate the proper syntax and usage.
This document discusses various data structures in R programming including vectors, matrices, arrays, data frames, lists, and factors. It provides examples of how to create each structure and access elements within them. Various methods for importing and exporting data in different file formats like Excel, CSV, and text files are also covered.
This document provides an overview of statistical concepts and analysis techniques in R, including measures of central tendency, data variability, correlation, regression, and time series analysis. Key points covered include mean, median, mode, variance, standard deviation, z-scores, quartiles, standard deviation vs variance, correlation, ANOVA, and importing/working with different data structures in R like vectors, lists, matrices, and data frames.
This document provides a summary of frequently used commands in Stata with brief explanations. Key commands are highlighted for importing, exploring, summarizing, and viewing data. Other sections cover manipulating strings, combining data, and reshaping data.
This document provides an overview of topics that will be covered in a two-day statistical programming course in R, including:
1. Vector and matrix operations, file input/output, and probability density functions.
2. Distributions like binomial, Poisson, normal and uniform as well as hypothesis testing using t, z, F, and chi-square.
3. Linear and multiple regression techniques, including prediction, residual analysis and modeling.
Case studies and examples are provided for many of these statistical techniques in R, such as linear regression, hypothesis testing, and probability distributions.
This document provides a summary of functions for input and output, data creation and manipulation, indexing, and getting help in R. Key functions covered include read.table() and read.csv() for reading data, c(), seq(), and rep() for data creation, [ and [[ for indexing vectors, lists and data frames, and help(), ? and apropos() for getting help documentation in R.
This document provides an overview of essential data wrangling tasks in R, including importing, exploring, indexing/subsetting, reshaping, merging, aggregating, and repeating/looping data. It discusses functions for reading different file types like CSV, Excel, and plain text. It also covers exploring data structure and summary statistics, subsetting vectors, data frames and matrices, reshaping between wide and long format, performing different types of joins to merge data, and using loops and sequences to repeat operations.
This document provides an overview of descriptive statistics and data visualization techniques using Python. It first describes summarizing a dataset using measures of central tendency, variation, skewness, and kurtosis. These include calculating the mean, median, mode, standard deviation, variance, and coefficient of variation. It then demonstrates bivariate analysis through scatter plots, correlation coefficients, and regression lines. Finally, it shows various data visualization graphs that can be created like bar charts, stacked and percentage bar charts, line and pie charts, box plots, histograms, stem-and-leaf plots, and heat maps using libraries like Pandas, Matplotlib and Seaborn.
This document provides a brief introduction to basic R features such as starting R, entering commands, importing and manipulating data, creating vectors and data frames, and performing summary statistics and visualizations. Key points covered include starting R, entering commands and comments, arithmetic operations, creating sequences and assigning objects, importing data from files, subsetting and manipulating vectors and data frames, and creating histograms, boxplots and other plots. Examples are provided using the built-in FlightDelays data set.
This presentation provides a brief introduction to data types and objects in R. I've not covered 'array' in the presentation, which is a multi-dimensional object [More general than matrix].
This document provides examples of different R data structures including vectors, matrices, lists, and data frames. Vectors are one-dimensional arrays that can contain only one data type. Matrices are two-dimensional arrays that can contain only one data type. Lists are collections of elements that can contain different data types. Data frames are two-dimensional structures similar to tables or spreadsheets that can contain different data types across rows and columns. The document demonstrates how to create, subset, and manipulate each of these structures through examples.
This document discusses various methods for importing, exporting, and summarizing data in Python using the Pandas library. It covers reading and writing CSV, TXT, and XLSX files with Pandas, checking the structure and dimensions of data frames, handling missing values, and modifying data through functions like rename(). The key methods described are read_csv(), read_table(), read_excel(), to_csv(), info(), isnull(), sum(), head(), tail(), and describe().
The document outlines various statistical and data analysis techniques that can be performed in R including importing data, data visualization, correlation and regression, and provides code examples for functions to conduct t-tests, ANOVA, PCA, clustering, time series analysis, and producing publication-quality output. It also reviews basic R syntax and functions for computing summary statistics, transforming data, and performing vector and matrix operations.
This document provides a summary of common functions and operations in R for input/output, data manipulation, indexing vectors and lists, and converting between data types. Key functions covered include print(), format(), write.table(), read.table(), c(), rep(), seq(), and data.frame() for creating and manipulating data. Indexing techniques allow extracting or replacing elements of vectors, matrices, data frames, and lists. Functions like str(), summary(), and dim() provide information about R objects.
RStudio is a trademark of RStudio, PBC. This document provides a cheat sheet on tidying data with the tidyr package in R. It defines tidy data as having each variable in its own column and each observation in its own row. It discusses tibbles as an enhanced data frame format and provides functions for constructing, subsetting, and printing tibbles. It also covers reshaping data through pivoting, handling missing values, expanding and completing data, and working with nested data through nesting, unnesting, and applying functions to list columns.
A short list of the most useful R commands
reference: http://www.personality-project.org/r/r.commands.html
R programı ile ilgilenen veya yeni öğrenmeye başlayan herkes için hazırlanmıştır.
- R is a free software environment for statistical computing and graphics. It has an active user community and supports graphical capabilities.
- R can import and export data, perform data manipulation and summaries. It provides various plotting functions and control structures to control program flow.
- Debugging tools in R include traceback, debug, browser and trace which help identify and fix issues in functions.
R can be used to analyze data and perform statistical analysis. Functions like help(), ? and help.start() provide information about other functions. Objects created in R sessions are stored by name and can be removed with rm(). Vectors like x=c(1,2,3,4,5) can be created and their length checked with length(x). Subsets of vectors can be selected using logical or integer indexes inside square brackets. Matrices are multi-dimensional generalizations of vectors that can be manipulated using operators like * and %. Data can be read into R from external files using functions like read.table() and read.delim(). Common statistical distributions like normal, uniform and exponential are available as functions in R for
R can be used to analyze data and perform statistical analysis. Key functions include help() and ? to get information on functions, and objects() to view stored objects. Vectors can be created with c() and manipulated using arithmetic operators. Matrices are two-dimensional arrays that can be operated on using *, /, and t(). Larger datasets are typically read from external files using read.table() or read.delim(). Common distributions can be explored using functions like dnorm(), pnorm(), and rnorm(). Statistical analysis includes commands like cov() and cor() to measure covariance and correlation between variables.
This document provides an introduction to manipulating tables in MySQL, including how to alter tables by adding, dropping, and modifying columns, how to insert and import data into tables from files using commands like INSERT, REPLACE, LOAD DATA INFILE and the mysqlimport utility, and how to perform updates and queries on table data using commands like UPDATE and SELECT. Examples are given for each task to demonstrate the proper syntax and usage.
This document discusses various data structures in R programming including vectors, matrices, arrays, data frames, lists, and factors. It provides examples of how to create each structure and access elements within them. Various methods for importing and exporting data in different file formats like Excel, CSV, and text files are also covered.
This document provides an overview of statistical concepts and analysis techniques in R, including measures of central tendency, data variability, correlation, regression, and time series analysis. Key points covered include mean, median, mode, variance, standard deviation, z-scores, quartiles, standard deviation vs variance, correlation, ANOVA, and importing/working with different data structures in R like vectors, lists, matrices, and data frames.
This document provides a summary of frequently used commands in Stata with brief explanations. Key commands are highlighted for importing, exploring, summarizing, and viewing data. Other sections cover manipulating strings, combining data, and reshaping data.
This document provides a reference card summarizing common functions and commands in R. It includes sections on miscellaneous commands, help functions, input and output, managing variables and objects, control flow, arithmetic, statistics, and graphics. Some key functions highlighted are parentheses for functions, brackets for vectors/matrices, q() to quit, <- for assignment, help() for documentation, source() to run code from a file, and plot() for basic plots.
This document provides a reference card summarizing many important functions in R for getting help, input/output, data creation and manipulation, mathematics, plotting, dates and times, strings, matrices, and advanced data processing. It describes what each function does and how to use it in just a few words.
This document provides a cheat sheet for frequently used commands in Stata for data processing, exploration, transformation, and management. It highlights commands for viewing and summarizing data, importing and exporting data, string manipulation, merging datasets, and more. Keyboard shortcuts for navigating Stata are also included.
This document provides a summary of key functions and commands in the R programming language for getting help, inputting and outputting data, creating and manipulating data, selecting and extracting data, performing mathematical operations, working with dates and times, plotting graphs, and more. It includes brief explanations and examples of commonly used functions like read.table(), plot(), hist(), summary(), str(), and others.
This document provides an introduction and overview of Stata, a statistical software package. It discusses what Stata is, the different versions of Stata, the Stata interface and how to navigate it. It also summarizes key functions for working with data in Stata, including importing and exporting data, exploring and managing variables, and conducting statistical analysis. The document is intended as a starting point for learning to use Stata.
The document defines data as values of variables that belong to a set of items. It discusses that data is the second most important thing in data science after the question. Having data does not ensure finding answers without a question to guide the analysis. It then provides an overview of topics in R programming for data extraction, exploration, modeling, and machine learning.
This document provides a cheat sheet for common commands and functions in R for data manipulation, statistical analysis, and graphics. It summarizes key topics such as accessing and manipulating data, conducting statistical tests, fitting linear and generalized linear models, performing clustering and multivariate analyses, and creating basic plots and graphics. The cheat sheet is organized into sections covering basics, vectors and data types, data frames, input/output, indexing, missing values, numerical and tabulation functions, programming, operators, graphics, and statistical models and distributions.
This document provides a concise reference card summarizing common functions and operations in R including getting help, input/output, data creation and manipulation, variable conversion and information, plotting, and dates/times. It covers essential functions for loading and saving data, accessing documentation, basic math operations, creating matrices and data frames, subsetting and selecting data, and creating basic plots and graphs.
This document provides a concise reference card summarizing common functions and operations in R including getting help, input and output, data creation, slicing and extracting data, variable conversion and information, data selection and manipulation, math operations, matrices, strings, dates and times, and plotting. It covers essential functions for loading and saving data, accessing documentation, basic data manipulation and common statistical analyses in R.
This document provides an overview of common functions and operations in R including getting help, input and output, data creation and manipulation, variable conversion and information, plotting, and dates and times. It summarizes key functions for loading and saving data, reading from and writing to files, creating vectors, matrices and data frames, subsetting and manipulating data, performing mathematical and statistical operations, working with strings, and creating basic plots. The document is intended as a quick reference guide to common tasks in R.
This reference card summarizes common R functions for getting help, inputting and outputting data, creating and manipulating data, extracting and selecting data, converting variables, getting variable information, and performing mathematical operations. It provides the syntax and brief description for many basic and commonly used R functions across these categories in 3 sentences or less per function.
Desk reference for data transformation in Stata. Co-authored with Tim Essam (@StataRGIS, linkedin.com/in/timessam). See all cheat sheets at http://bit.ly/statacheatsheets. Updated 2016/06/03.
This document provides an overview of R programming. It discusses that R was developed in 1993 and is made up of libraries for data science. It covers basic R data types like vectors, matrices, data frames, and lists. It also describes how to import and export data from files in R and introduces several machine learning algorithms like Naive Bayes, decision trees, and k-means clustering.
This document provides an introduction to using R and RStudio. It discusses installing R and RStudio, the four windows in RStudio (source editor, console, environment/history, and plots/files), and basic commands and functions for running code, saving scripts, clearing the screen, commenting lines, and getting help. It also covers creating and manipulating variables and vectors, importing and exporting data, generating basic plots like bar plots, pie charts and histograms, and importing/exporting data.
This document provides an introduction to the statistical programming language R. It outlines what R is, how to access and use its interface, and how to work with basic data types like vectors, matrices, and factors. It also demonstrates how to import and export data, perform basic plotting and graphics, and gives examples working with biological data from Affymetrix chips. The presenter encourages attendees to ask questions and notes they are not a perfect teacher.
The document is a cheat sheet for data wrangling with pandas, providing syntax and examples for common data wrangling tasks like creating and reshaping DataFrames, subsetting data, combining datasets, filtering and joining data, grouping data, handling missing values, and creating plots. It covers topics such as creating DataFrames from lists or dictionaries, melting and pivoting data, sorting and ordering rows, subsetting rows and columns, merging datasets, and applying functions across columns or groups.
The document is a cheat sheet for data wrangling with pandas, providing syntax and methods for creating and manipulating DataFrames, reshaping and subsetting data, summarizing data, combining datasets, filtering and joining data, grouping data, handling missing values, and plotting data. Key methods described include pd.melt() to gather columns into rows, pd.pivot() to spread rows into columns, pd.concat() to append DataFrames, df.sort_values() to order rows by column values, and df.groupby() to group data.
Conference Paper:IMAGE PROCESSING AND OBJECT DETECTION APPLICATION: INSURANCE...Dr. Volkan OBAN
1) The document discusses using image processing and object detection techniques for insurance claims processing and underwriting. It aims to allow insurers to realistically assess images of damaged objects and claims.
2) Artificial intelligence, including computer vision, has been widely adopted in the insurance industry to analyze data like images, extract relevant information, detect fraud, and predict costs. Computer vision can recognize objects in images and help route insurance inquiries.
3) The document examines several computer vision applications for insurance - image similarity, facial recognition, object detection, and damage detection from images. It asserts that computer vision can expedite claims processing and improve key performance metrics for insurers.
Covid19py by Konstantinos Kamaropoulos
A tiny Python package for easy access to up-to-date Coronavirus (COVID-19, SARS-CoV-2) cases data.
ref:https://github.com/Kamaropoulos/COVID19Py
https://pypi.org/project/COVID19Py/?fbclid=IwAR0zFKe_1Y6Nm0ak1n0W1ucFZcVT4VBWEP4LOFHJP-DgoL32kx3JCCxkGLQ
This document provides examples of object detection output from a deep learning model. The examples detect objects like cars, trucks, people, and horses along with confidence scores. The document also mentions using Python and TensorFlow for object detection with deep learning. It is authored by Volkan Oban, a senior data scientist.
The document discusses using the lpSolveAPI package in R to solve linear programming problems. It provides three examples:
1) A farmer's profit maximization problem is modeled and solved using functions from lpSolveAPI like make.lp(), add.constraint(), and solve().
2) A simple minimization problem is created and solved to illustrate setting up the objective function and constraints.
3) A more complex problem is modeled to demonstrate setting sparse matrices, integer/binary variables, and customizing variable and constraint names.
"optrees" package in R and examples.(optrees:finds optimal trees in weighted ...Dr. Volkan OBAN
Finds optimal trees in weighted graphs. In
particular, this package provides solving tools for minimum cost spanning
tree problems, minimum cost arborescence problems, shortest path tree
problems and minimum cut tree problem.
by Volkan OBAN
k-means Clustering in Python
scikit-learn--Machine Learning in Python
from sklearn.cluster import KMeans
k-means clustering is a method of vector quantization, originally from signal processing, that is popular for cluster analysis in data mining. k-means clustering aims to partition n observations into k clusters in which each observation belongs to the cluster with the nearest mean, serving as a prototype of the cluster. This results in a partitioning of the data space into Voronoi cells.
The problem is computationally difficult (NP-hard); however, there are efficient heuristic algorithms that are commonly employed and converge quickly to a local optimum. These are usually similar to the expectation-maximization algorithm for mixtures of Gaussian distributions via an iterative refinement approach employed by both algorithms. Additionally, they both use cluster centers to model the data; however, k-means clustering tends to find clusters of comparable spatial extent, while the expectation-maximization mechanism allows clusters to have different shapes.[wikipedia]
ref: http://scikit-learn.org/stable/auto_examples/cluster/plot_cluster_iris.html
This document describes using time series analysis in R to model and forecast tractor sales data. The sales data is transformed using logarithms and differencing to make it stationary. An ARIMA(0,1,1)(0,1,1)[12] model is fitted to the data and produces forecasts for 36 months ahead. The forecasts are plotted along with the original sales data and 95% prediction intervals.
k-means Clustering and Custergram with R.
K Means Clustering is an unsupervised learning algorithm that tries to cluster data based on their similarity. Unsupervised learning means that there is no outcome to be predicted, and the algorithm just tries to find patterns in the data. In k means clustering, we have the specify the number of clusters we want the data to be grouped into. The algorithm randomly assigns each observation to a cluster, and finds the centroid of each cluster.
ref:https://www.r-bloggers.com/k-means-clustering-in-r/
ref:https://rpubs.com/FelipeRego/K-Means-Clustering
ref:https://www.r-bloggers.com/clustergram-visualization-and-diagnostics-for-cluster-analysis-r-code/
Data Science and its Relationship to Big Data and Data-Driven Decision MakingDr. Volkan OBAN
Data Science and its Relationship to Big Data and Data-Driven Decision Making
To cite this article:
Foster Provost and Tom Fawcett. Big Data. February 2013, 1(1): 51-59. doi:10.1089/big.2013.1508.
Foster Provost and Tom Fawcett
Published in Volume: 1 Issue 1: February 13, 2013
ref:http://online.liebertpub.com/doi/full/10.1089/big.2013.1508
https://www.researchgate.net/publication/256439081_Data_Science_and_Its_Relationship_to_Big_Data_and_Data-Driven_Decision_Making
The Pandas library provides easy-to-use data structures and analysis tools for Python. It uses NumPy and allows import of data into Series (one-dimensional arrays) and DataFrames (two-dimensional labeled data structures). Data can be accessed, filtered, and manipulated using indexing, booleans, and arithmetic operations. Pandas supports reading and writing data to common formats like CSV, Excel, SQL, and can help with data cleaning, manipulation, and analysis tasks.
ReporteRs package in R. forming powerpoint documents-an exampleDr. Volkan OBAN
This document contains examples of plots, FlexTables, and text generated with the ReporteRs package in R to create a PowerPoint presentation. A line plot is generated showing ozone levels over time. A FlexTable is created from the iris dataset with styled cells and borders. Sections of formatted text are added describing topics in data science, analytics, and machine learning.
ReporteRs package in R. forming powerpoint documents-an exampleDr. Volkan OBAN
This document contains examples of plots, FlexTables, and text generated with the ReporteRs package in R to create a PowerPoint presentation. A line plot is generated showing ozone levels over time. A FlexTable is created from the iris dataset with styled cells and borders. Sections of formatted text are added describing topics in data science, analytics, and machine learning.
R Machine Learning packages( generally used)
prepared by Volkan OBAN
reference:
https://github.com/josephmisiti/awesome-machine-learning#r-general-purpose
State of Artificial intelligence Report 2023kuntobimo2016
Artificial intelligence (AI) is a multidisciplinary field of science and engineering whose goal is to create intelligent machines.
We believe that AI will be a force multiplier on technological progress in our increasingly digital, data-driven world. This is because everything around us today, ranging from culture to consumer products, is a product of intelligence.
The State of AI Report is now in its sixth year. Consider this report as a compilation of the most interesting things we’ve seen with a goal of triggering an informed conversation about the state of AI and its implication for the future.
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Research: Technology breakthroughs and their capabilities.
Industry: Areas of commercial application for AI and its business impact.
Politics: Regulation of AI, its economic implications and the evolving geopolitics of AI.
Safety: Identifying and mitigating catastrophic risks that highly-capable future AI systems could pose to us.
Predictions: What we believe will happen in the next 12 months and a 2022 performance review to keep us honest.
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Talk Delivered at Valencia Codes Meetup 2024-06.
Traditionally, databases have treated timestamps just as another data type. However, when performing real-time analytics, timestamps should be first class citizens and we need rich time semantics to get the most out of our data. We also need to deal with ever growing datasets while keeping performant, which is as fun as it sounds.
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1. The Ultimate R Cheat Sheet – Data Management (Version 4)
Google “R Cheat Sheet” for alternatives. The best cheat sheets are those that you make yourself!
Arbitrary variable and table names that are not part of the R function itself are highlighted in bold.
Import, export, and quick checks
dat1=read.csv("name.csv") to import a standard CSV file (first row are variable names).
attach(dat1) to set a table as default to look for variables. Use detach() to release.
dat1=read.delim("name.txt") to import a standard tab-delimited file.
dat1=read.fwf("name.prn", widths=c(8,8,8)) fixed width (3 variables, 8 characters wide).
?read.table to find out more options for importing non-standard data files.
dat1=read.dbf("name.dbf") requires installation of the foreign package to import DBF files.
head(dat1) to check the first few rows and variable names of the data table you imported.
names(dat1) to list variable names in quotation marks (handy for copy and paste to code).
data.frame(names(dat1)) gives you a list of your variables with the column number indicated,
which can be handy for sub-setting a data table (see next page)
nrow(dat1) and ncol(dat1) returns the number of rows and columns of a data table.
length(dat1$VAR1[!is.na(dat1$VAR1)] returns a count of non-missing values in a variable.
str(dat1) to check variable types, which is useful to see if the import executed correctly.
write.csv(results, "myresults.csv", na="", row.names=F) to export data. Without
the option statements, missing values will be represented by NA and row numbers will be written out.
Data types and basic data table manipulations
There are three important variable types: numeric, character and factor (a double variable with
a numeric and character value). You can query or assign types: is.factor() or as.factor().
If you import a data table, variables that contain one or more character entries will be set to factor.
You can force them to numeric with this: as.numeric(as.character(dat1$VAR1))
After subsetting or modification, you might want to refresh factor levels with droplevels(dat1)
Data tables can be set as.data.frame(), as.matrix(), as.distance()
names(dat1)=c("ID", "X", "Y", "Z") renames variables. Note that the length of the vector
must match the number of variable you have (four in this case).
row.names(dat1)=dat1$ID. assigns an ID field to row names. Note that the default row names
are consecutive numbers. In order for this to work, each value in the ID field must be unique.
To generate unique and descriptive row names that may serve as IDs, you can combine two or more
variables: row.names(dat1)=paste(dat1$SITE, dat1$PLOT, sep="-")
If you only have numerical values in your data table, you can transpose it (switch rows and columns):
dat1_t=t(dat1). Row names become variables, so run the row.names() function above first.
dat1[order(X),] orders rows by variable X. dat[order(X,Y),] orders rows by variable X, then
variable Y. dat1[order(X,-Y),]. Orders rows by variable X, then descending by variable Y.
fix(dat1) to open the entire data table as a spreadsheet and edit cells with a double-click.
Creating systematic data and data tables
c(1:10) is a generic concatenate function to create a vector, here numbers from 1 to 10.
seq(0, 100, 10) generates a sequence from 0 to 100 in steps of 10.
rep(5,10) replicates 5, 10 times. rep(c(1,2,3),2) gives 1 2 3 1 2 3. rep(c(1,2,3),
each=2) gives 1 1 2 2 3 3. This can be useful to create data entry sheets for experimental designs.
data.frame(VAR1=c(1:10), VAR2=seq(10, 100, 10), VAR3=rep( c("this",
"that"),5)) creates a data frame from a number of vectors.
expand.grid(SITE=c("A","B"),TREAT=c("low","med","high"), REP=c(1:5)) is an
elegant method to create systematic data tables.
2. Creating random data and random sampling
rnorm(10) takes 10 random samples from a normal distribution with a mean of zero and a standard
deviation of 1
runif(10) takes 10 random samples from a uniform distribution between zero and one.
round(rnorm(10)*3+15)) takes 10 random samples from a normal distribution with a mean of 15
and a standard deviation of 3, and with decimals removed by the rounding function.
round(runif(10)*5+15) returns random integers between 15 and 20, uniformly distributed.
sample(c("A","B","C"), 10, replace=TRUE) returns a random sample from any custom
vector or variable with replacement.
sample1=dat1[sample(1:nrow(dat1), 50, replace=FALSE),] takes 50 random rows from
dat1 (without duplicate sampling). This can be handy for bootstrapping or to run quick test analyses
on subsets of very large datasets.
Sub-setting data tables, conditional subsets
dat1[1:10, 1:5] returns the first 10 rows and the first 5 columns of table dat1.
dat2=dat1[50:70,] returns a subset of rows 50 to 70.
cleandata=dat1[-c(2,7,15),] removes rows 2, 7 and 15.
selectvars=dat1[,c("ID","YIELD")] sub-sets the variables ID and YIELD
selectrows=dat1[dat1$VAR1=="Site 1",] sub-sets entries that were measured at Site 1.
Possible conditional operators are == equal, != non-equal, > larger, < smaller, >= larger or equal, <=
smaller or equal, & AND, | OR, ! NOT, () brackets to order complex conditional statements.
selecttreats=dat1[dat1$TREAT %in% c("CTRL", "N", "P", "K"),] can replace
multiple conditional == statements linked together by OR.
Transforming variables in data tables, conditional transformations
dat2=transform(dat1, VAR1=VAR1*0.4). Multiplies VAR1 by 0.4
dat2=transform(dat1, VAR2=VAR1*2). Creates variable VAR2 that is twice the value of VAR1
dat2=transform(dat1, VAR1=ifelse(VAR3=="Site 1", VAR1*0.4, VAR1)) Multiplies
VAR1 by 0.1 for entries measured at Site 1. For other sites the value stays the same. The general
format is ifelse(condition, value if true, value if false).
The vegan package offers many useful standard transformations for variables or an entire data table:
dat2=decostand(dat1,"standardize") Check out ?decostand to see all transformations.
Merging data tables
dat3=merge(dat1,dat2,by="ID") merge two tables by ID field.
dat3=merge(dat1,dat2,by.x="ID",by.y="STN") merge by an ID field that is differently
named in the two datasets.
dat3=merge(dat1,dat2,by=c("LAT","LONG")) merge by multiple ID fields.
dat3=merge(dat1,dat2,by.x="ID",by.y="ID",all.x=T,all.y=F) left merge; all.x=F,
all.y=T right merge; all.x=T,all.y=T keep all rows; all.x=F,all.y=F keep matching rows.
cbind(dat1,dat2) On very rare occasions, you merge data without a criteria (ID). This is generally
dangerous, because the commands will slap the two tables together without checking the order!
dat3=rbind(dat1,dat2) adding rows of two data tables. The variables have to match exactly and
you will get error messages if they don’t match. So, unlike cbind(), rbind() is generally safe to use.
dat3=rbind.fill(dat1,dat2) will force non-matching datasets together, filling missing values
and executing variable type conversions where appropriate. Requires the reshape package.
Summary statistics for variables and tables
mean() weighted.mean(,) median() max() min() range() which.max()
which.min() var() sd() quantile() quantile(,c(0.025,0.05,0.95,0.975))
rank(x) some descriptive statistical functions for variables or vectors. For all functions, and
3. important option is na.rm=T, which means that missing values are ignored in the calculations, e.g.
mean(VAR1, na.rm=T). Without that option, the function returns missing values as a result of
missing values in the input.
rowSums(), colSums(), rowMeans() or colMeans() applies functions to rows or columns of a
table. For example, rowsum(dat1[,10:15]) will return the row-sums of the variables in columns
10 to 15. Don’t forget na.rm=T.
apply(dat,1,max) apply any function (e.g. max), to either rows (1) or columns (2) of a table (dat).
Pivot table functionality
The functions aggregate and ddply can be used to summarize data similarly to working with Excel
pivot tables. Aggregate has simpler syntax if you have many variables that you want to summarize in
the same way; ddply is better if you have few variables but want several custom summary statistics.
aggregate(dat1[,4:9], by=list(TREAT1=dat1$TREAT1, TREAT2=dat2$TREAT2),
mean) calculates the means of a number of numerical variables in columns 4 to 9 for two treatments.
ddply(dat1,.(TREAT), summarise, mVAR1=mean(VAR1)) returns means of VAR1 by a class
variables TREAT. This requires installation of the library plyr.
ddply(dat1,.(TREAT1, TREAT2), summarise, cVAR1=length(VAR1[!is.na(VAR1)])
returns a count of non-missing values in variable VAR1 for each combination of two class variables.
ddply(dat1,.(TREAT1, TREAT2), summarise, mVAR1=mean(VAR1, na.rm=T),
seVAR1=sd(VAR1, na.rm=T)/sqrt(length(VAR1[!is.na(VAR1)])). A clever piece of code
to calculate means and standard errors, with missing values being properly handled.
Long-to-wide and wide-to-long data table conversions
First we generate an artificial dataset to play with (copy and paste to R to see what it does):
long=expand.grid(SITE=c("A","B"),TREAT=c("low","med","high"), REP=c(1:5))
long$YIELD=round(rnorm(10)*5+15); long
Long-to-wide conversion with the reshape2 package, where SITE and REP remain columns, but the
treatment levels of TREAT now become several new columns:
wide=dcast(long, SITE+REP~TREAT, value.var="YIELD")
Wide-to-long conversion back to what we had before. The variables that you want to maintain as
columns are SITE and REP, all others will be gathered into a new variable where the remaining
columns become treatment levels. You have to fix the variable names to get to the original long:
long2=melt(wide, id.vars=c("SITE","REP"))
names(long2)=c("SITE","REP","TREAT","YIELD")
Dealing with missing values
transform(dat1, VAR1=ifelse(is.na(VAR1),0,VAR1)) sets missing values in variable
VAR1 to 0. You may do this if missing has a biological meaning of zero, e.g. zero productivity.
transform(dat1, VAR1=ifelse(VAR1==0,NA,VAR1)) … or vice versa if zero really means
that the measurement was not taken.
dat1[is.na(dat1)]=0 sets missing values to 0 in entire dataset.
dat1[dat1==0]=NA ... vice versa.
dat2=na.omit(dat1) delete rows with missing values in any variable
dat2=dat1[!is.na(dat1$VAR1),] delete rows with missing values in VAR1
dat2=transform(dat1, VAR2=ifelse(is.na(VAR1),NA,VAR2))modify a second variable
(here: set to missing) based on missing values in a first variable.
Dealing with duplicate data entries or IDs:
unique(dat1) or dat1[!duplicated(dat1),] removes exact duplicate rows.
dat1[duplicated(dat1),] returns the duplicate rows.
dat1[!duplicated(dat1[,c("ID")]),] removes all rows with duplicate IDs (first is kept).
dat1[duplicated(dat1[,c("ID")]),] returns the rows with duplicate IDs.
4. Loops and automation
v1=vector(length=20) initializes an empty vector with 20 elements. This is often required as an
initial statement to subsequently write results of a loop into an output vector or output table.
m1=matrix(nrow=20, ncol=10) similarly initializes an empty matrix with 20 rows and 10
columns.
for (i in 1:10) { one or more operations with v1[i] or m1[,i] }
for (i in 1:10) { for (j in 1:20) { one or more operations with m1[j,i] }}
Example for an application, where a for-loop is used to calculate cumulative values. Copy and paste
the code below into R to see what it does.
dat=round(rnorm(10)+2)
cum=vector(length=10)
cum[1]=dat[1]
for (i in 2:length(dat)) { cum[i]=cum[i-1]+dat[i] }
cbind(dat,cum)
Example for an application where a for-loop allows automatic data processing of multiple files in a
directory. This batch-converts DBF format files into CSV format files. With similar code, you could
merge a large number of files into one master file, or do manipulations or analysis on multiple files
consecutively.
library(foreign)
setwd("C:/your path/")
a<-list.files(); a
for (name in a) { dat1=read.dbf(name)
write.csv(dat1, paste(name,".csv"), row.names=F, quote=F) }
Handy built-in functions
paste("hello", "world") joins vectors after converting them to characters. The sep="" option
can place any character string or nothing between values (a single space is the default)
substr("Year 1998",6,9) extracts characters from start to stop position from vector
tolower("Year 1998") convert to lowercase - handy to correct inconsistencies in data entry.
toupper("Year 1998") convert to uppercase
nchar("Year 1998") number of characters in a string, allows you to substring the last four digits
of a variable regardless of length, for example: substr(VAR1,nchar(VAR1)-3,nchar(VAR1))
Plenty of math functions, of course: log(VAR1), log10(VAR1), log(VAR1,2), exp(VAR1),
sqrt(VAR1), abs(VAR1), round(VAR1,2)
Programming custom functions
You can program your own functions, if something is missing, or if you want to utilize a bunch of code
over and over to make similar calculations. Here is a clever example for calculating the statistical
mode of a variable, which is missing from the built-in R functions.
mode=function(input){ freq=table(as.vector(input))
descending_freq=sort(-freq)
mode=names(descending_freq)[1]
as.numeric(mode)
}
VAR1=c(1,3,3,2,3,2,2,3,5,3)
mode(VAR1)
More information, help, and on-line resources
Adding a question mark before a command or functions brings up a help file. E.g. ?paste. Be sure to
check out the example code at the end of the help file, which often helps to understand the syntax.
More information and R resources can be found with the search engine http://www.rseek.org