Learn to manipulate numbers in R using the built in numeric functions. This tutorial is part of the Working With Data module of the R Programming course offered by r-squared.

1. r-squared
Slide 1 www.r-squared.in/rprogramming
R Programming
Learn the fundamentals of data analysis with R.

2. r-squared
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Course Modules
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✓ Introduction
✓ Elementary Programming
✓ Working With Data
✓ Selection Statements
✓ Loops
✓ Functions
✓ Debugging
✓ Unit Testing

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Working With Data
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✓ Data Types
✓ Data Structures
✓ Data Creation
✓ Data Info
✓ Data Subsetting
✓ Comparing R Objects
✓ Importing Data
✓ Exporting Data
✓ Data Transformation
✓ Numeric Functions
✓ String Functions
✓ Mathematical Functions

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In this unit, we will explore the following numeric functions:
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Numeric Functions
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● signif()
● jitter()
● format()
● formatC()
● abs()
● round()
● ceiling()
● floor()

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abs()
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Description
abs() computes the absolute values of its arguments.
Syntax
abs(x)
Returns
Absolute value
Documentation
help(abs)

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abs()
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Examples
> # example 1
> x <- -5
> abs(x)
[1] 5
> # example 2
> y <- 5
> abs(y)
[1] 5
> # example 3
> z <- c(1, -3, 4, -7, 5, -9)
> abs(z)
[1] 1 3 4 7 5 9

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round()
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Description
round() rounds its argument to the specified number of decimal places.
Syntax
round(x, digits)
Returns
Argument rounded to specified number of decimal places.
Documentation
help(round)

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round()
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Examples
> # example 1
> x <- 5.3645
> round(x) # zero decimal values
[1] 5
> round(x, digits = 1) # one decimal values
[1] 5.4
> round(x, digits = 2) # two decimal values
[1] 5.36
> round(x, digits = 3) # three decimal values
[1] 5.364

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ceiling()
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Description
ceiling() takes a numeric argument x and returns the smallest integer not less than x.
Syntax
ceiling(x)
Returns
Integer
Documentation
help(ceiling)

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ceiling()
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Examples
> example 1
> x <- 5.3645
> ceiling(x)
[1] 6
> example 2
> x <- 3.94
> ceiling(x)
[1] 4
> example 3
> x
[1] 7.012865 8.148132 9.840098 2.965393 2.098276 6.139226 3.819461 8.849482 1.068249
[10] 5.105874
> ceiling(x)
[1] 8 9 10 3 3 7 4 9 2 6

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floor()
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Description
floor() takes a numeric argument x and returns the smallest integer not greater than x.
Syntax
floor(..., collapse = NULL)
Returns
Integer
Documentation
help(floor)

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floor()
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Examples
> # example 1
> x <- 5.3645
> floor(x)
[1] 5
> # example 2
> x <- 3.94
> floor(x)
[1] 3
> # example 3
> x <- sample(jitter(1:10))
> x
[1] 6.1581438 9.9260513 0.9823364 4.1083687 4.9102557 8.1316709 7.0094556 2.8870083
[9] 2.1403249 9.0941759
> floor(x)
[1] 6 9 0 4 4 8 7 2 2 9

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trunc()
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Description
trunc() takes a numeric argument and returns the first integer as the values is truncated
towards zero.
Syntax
trunc(x)
Returns
Integer
Documentation
help(trunc)

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trunc()
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Examples
> # example 1
> x <- 5.3645
> trunc(x)
[1] 5
# as we truncate the value in x towards zero, the first integer that appears is 5.
> # example 2
> x <- -3.94
> trunc(x)
[1] -3
> round(x)
[1] -4
> floor(x)
[1] -4
# as we truncate the value in x towards zero, the first integer that appears is -3.

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signif()
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Description
signif() rounds the value in the first argument to the specified number of significant
digits.
Syntax
signif(x, digits)
Returns
Value with specified number of significant digits
Documentation
help(signif)

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signif()
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Examples
> # example
> x <- 5.3645
> signif(x, 1)
[1] 5
> signif(x, 2)
[1] 5.4
> signif(x, 3)
[1] 5.36

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jitter()
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Description
jitter() add noise to a numeric vector.
Syntax
jitter(numeric_vector)
Returns
Numeric vector with noise
Documentation
help(jitter)

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jitter()
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Examples
> # example 1
> x <- 1:10
> x
[1] 1 2 3 4 5 6 7 8 9 10
> jitter(x)
[1] 1.198246 1.845626 3.171562 3.809923 5.188604 6.171728 7.022194 8.058092
[9] 9.150582 10.142704

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format()
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Description
format() will format an R object for pretty printing.
Syntax
format(x, digits, nsmall, justify)
Returns
Formatted object
Documentation
help(format)

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format()
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Examples
> # example 1
> x
[1] 1.187272 2.080868 3.197517 4.016246 4.979482 6.163807 6.837692 8.013903 8.864735
[10] 9.939144
> format(x, digits = 3)
[1] "1.19" "2.08" "3.20" "4.02" "4.98" "6.16" "6.84" "8.01" "8.86" "9.94"
> # example 2
> x <- 1:10
> format(x)
[1] " 1" " 2" " 3" " 4" " 5" " 6" " 7" " 8" " 9" "10"
> format(x, trim = TRUE)
[1] "1" "2" "3" "4" "5" "6" "7" "8" "9" "10"

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format()
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Examples
> # example 3
> format(6.5)
[1] "6.5"
> format(6.5, nsmall = 3)
[1] "6.500"
> format(c(6.5, 15.3), digits = 2)
[1] " 6.5" "15.3"
> format(c(6.5, 15.3), digits = 2, nsmall = 1)
[1] " 6.5" "15.3"

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formatC()
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Description
formatC() formats numbers individually and flexibly.
Syntax
formatC(x, digits, width)
Returns
Formatted object
Documentation
help(formatC)

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formatC()
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Examples
> # example 1
> x <- 1:10
> formatC(x)
[1] "1" "2" "3" "4" "5" "6" "7" "8" "9" "10"
> formatC(x, width = 6)
[1] " 1" " 2" " 3" " 4" " 5" " 6" " 7" " 8" " 9"
[10] " 10"
> # example 2
> x <- sample(jitter(1:10))
> x
[1] 7.0094486 0.9592379 5.8403164 8.8848952 4.9665959 9.9507841 3.1295332 7.8283830
[9] 2.1360850 3.8991551
> formatC(x, digits = 4)
[1] "7.009" "0.9592" " 5.84" "8.885" "4.967" "9.951" " 3.13" "7.828" "2.136"
[10] "3.899"

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In the next unit, we will explore string manipulation in R using the following functions:
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Next Steps...
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● match()
● char.expand()
● grep()
● grepl()
● sub()
● substr()
● substring()
● strsplit()
● strtrim()
● chartr()
● tolower()
● toupper()
● toString()
● nchar()
● nzchar()
● noquote()
● pmatch()
● charmatch()

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