Anomit Ghosh        Dhananjay Singh   Ankur Shrivastava
anomit@anomit.com   mail@djsh.net     ankur@ankurs.com
What We Will Learn

    History, Features and Basic Details
●



    Language Basics
●



    Control flow
●



    Functi...
What is Python?

    Python is a general purpose, object
●


    oriented, high level, interpreted
    language

    Devel...
Where is it used?

    Google uses it for its web crawler
●


    and search engine

    Youtube is based on Python
●



 ...
Diff from C/C++/Java

    No   Pointers (similar to java)
●



    No prior Compilation to
●


    ByteCode(?), directly I...
Versions Of Python

    What Do You mean By Versions??
●




    Major/Important Versions Currently

    Python 2.5
●



 ...
Why 2.5/2.6 and !3.0???

    Available on a Large Number of
●


    Systems

    Major Library's and Extensions
●


    av...
Python Interpreter

    Interactive session

    What is it?
●



    Their Importance
●



    How to exit an Interactive...
Language Basics
Indentation

    Indentation is very important
●



    There are no begin/end delimiters
●



    Physical lines & Logica...
Data Types

    Integer Numbers –> (dec) 1, 44;
●


    (oct) 01, 022;(hex) 0x1, 0x23;
    (long) 1L, 344343L

    Floatin...
Strings

    Strings can be single (',”) or triple
●


    (''',”””) quoted

    Character escaping by 
●



    Escape se...
Tuple
    It is an Immutable(?) ordered
●


    sequence of items(?)

    Assigned-> a = (1122,1212,1212)
●



    Using t...
Lists

    List is a mutable ordered sequence
●


    of items (similar to tuple)

    Assigned-> a = [121,121212,34367]
●...
Dictionaries
    Dictionaries are containers, which
●


    store items in a key/value pair(?)

    Assigned -> d ={'x':24...
Variables
    There is no prior declaration needed
●



    Variables are the references(?) to
●


    the allocated memor...
Index and slices
    String, List, Tuple, etc can be
●


    sliced to get a part of them

    Index -> similar to array i...
Control Flow
print

    Print is a simple statement for
●


    giving output similar to C's printf
    function

    Can be used to ou...
input

    Use raw_input() to take a string
●


    input from the user

    Used as
●



    <var> = raw_input(“Enter a S...
if
    If is a conditional statement, for
●


    simple “If then else“ clause in English

    Header lines(?) are always ...
If (con)
    Example->
●



    if <condition>:
●



        Statement 1
        Statement 2

    elif <condition>:
      ...
while
    While statement is used for
●


    repeatedly executing a block of code
    till the condition is true, also ha...
While (con)
    Example ->
●



    While <condition>:
●



        statements

    else:
        statements
for
    It is a sequence iterator(?)
●



    It works on Strings, lists, tuples,
●


    etc

    Example->
●



    For ...
range/xrange

    They are used to generate and
●


    return integer sequence(?)

    Range(5) -> [0,1,2,3,4]
●



    R...
break

    Used to terminate a loop
●



    If nested(?) it terminates the inner
●


    most loop

    Practically used ...
continue

    Terminates the current iteration and
●


    executes next

    Practically used for conditional
●


    sta...
Some Helpful Functions

    Dir()
●



    Help()
●
Functions
What are functions?

    A Function is a group of statements
●


    that execute on request

    In Python Functions are ...
Parameters

    Types of parameters
●



       Mandatory Parameters
       Optional parameters

    Defaults values
●



...
Example

    Def a(x,y=[]):
●



       y.append(x)
       print y

    print a(12)

    print a(34)

    What just happen...
Namespace

    A namespace is an abstract container
●


    or environment created to hold a
    logical grouping of uniqu...
Nested Functions

    Def statement inside a function
●


    defines a nested function

    Useful sometimes
●



    Use...
Functions (con)

    Return
●



    Return Type
●



    Some Examples
●
Modules
Modules

    What are modules?
●



    How to load modules
●



    Effect on namespace
●



    Important modules
●



 ...
How To Make Modules?
Y is this Important
Python Workshop. LUG Maniapl
Python Workshop. LUG Maniapl
Python Workshop. LUG Maniapl
Python Workshop. LUG Maniapl
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Python Workshop. LUG Maniapl

  1. 1. Anomit Ghosh Dhananjay Singh Ankur Shrivastava anomit@anomit.com mail@djsh.net ankur@ankurs.com
  2. 2. What We Will Learn History, Features and Basic Details ● Language Basics ● Control flow ● Functions ● Modules ● Data Structures ● File I/O ●
  3. 3. What is Python? Python is a general purpose, object ● oriented, high level, interpreted language Developed in early 90's by Guido Van ● Rossum Its Simple, Portable, Open Source ● and Powerful
  4. 4. Where is it used? Google uses it for its web crawler ● and search engine Youtube is based on Python ● Disney uses it in Panda3d ● Bittorrent is implemented in Python ● Used extensively from Space Shuttles ● to Mobile Phones
  5. 5. Diff from C/C++/Java No Pointers (similar to java) ● No prior Compilation to ● ByteCode(?), directly Interpreted Includes Garbage Collector(?) ● Can be used in Procedure(?)/ ● Object(?) Oriented approach/style Very good for scripting ●
  6. 6. Versions Of Python What Do You mean By Versions?? ● Major/Important Versions Currently Python 2.5 ● Python 2.6 ● Python 3.0 ● So what will we use??
  7. 7. Why 2.5/2.6 and !3.0??? Available on a Large Number of ● Systems Major Library's and Extensions ● available for 2.5/2.6 not 3.0 <<<<MORE>>>> ●
  8. 8. Python Interpreter Interactive session What is it? ● Their Importance ● How to exit an Interactive session ● quit() or Ctrl + D on Unix-like Systems Ctrl + Z on windows
  9. 9. Language Basics
  10. 10. Indentation Indentation is very important ● There are no begin/end delimiters ● Physical lines & Logical lines ● Joining physical lines by / ● Use # for comments ●
  11. 11. Data Types Integer Numbers –> (dec) 1, 44; ● (oct) 01, 022;(hex) 0x1, 0x23; (long) 1L, 344343L Floating Point -> ● 0.,0.0,323.23,2e3,23e32 Complex numbers –> j = (-1) 1/2 ● 10+10j, -1+5j, 5-6j
  12. 12. Strings Strings can be single (',”) or triple ● (''',”””) quoted Character escaping by ● Escape sequence - , ', ”, ● n, t
  13. 13. Tuple It is an Immutable(?) ordered ● sequence of items(?) Assigned-> a = (1122,1212,1212) ● Using tuples –> can be used as a ● constant array (but are much more) Data can be accessed similar to an ● array -> a=(132,3232,323) a[1] or a[3]
  14. 14. Lists List is a mutable ordered sequence ● of items (similar to tuple) Assigned-> a = [121,121212,34367] ● Using Lists -> simplest use is a ● arrays (but again are much more) Data can be accessed similar to an ● array -> a=[132,3232,323] a[1] or a[3]
  15. 15. Dictionaries Dictionaries are containers, which ● store items in a key/value pair(?) Assigned -> d ={'x':24,'y':33} ● Using Dict -> They are used at a ● lot of places (covered later) Data can be accessed by using the ● key -> d['x']
  16. 16. Variables There is no prior declaration needed ● Variables are the references(?) to ● the allocated memory(?) Variables can refer to any data type ● (like Tuple, List,Dictionary, Int, String, Complex) References are share ● List,Dict etc are always shared ●
  17. 17. Index and slices String, List, Tuple, etc can be ● sliced to get a part of them Index -> similar to array index, it ● refers to 1 position of data Slices-> gives the data in the range ● Example -> ● a=”LUG Manipal” a[:3] a[4:11] a[4:] a[-7:] a[:-8] a[:11:2]
  18. 18. Control Flow
  19. 19. print Print is a simple statement for ● giving output similar to C's printf function Can be used to output to Console ● or a file Use -> print “Hello World” ●
  20. 20. input Use raw_input() to take a string ● input from the user Used as ● <var> = raw_input(“Enter a String: “) Input() in used to take a input ● without specifying the type
  21. 21. if If is a conditional statement, for ● simple “If then else“ clause in English Header lines(?) are always concluded ● with a “ : “ followed by intended block of statements Optionally it can be followed by an ● “else if” clause known as “elif” in python
  22. 22. If (con) Example-> ● if <condition>: ● Statement 1 Statement 2 elif <condition>: Statements else: statements
  23. 23. while While statement is used for ● repeatedly executing a block of code till the condition is true, also has an optional else clause Use wildly for infinite loop ●
  24. 24. While (con) Example -> ● While <condition>: ● statements else: statements
  25. 25. for It is a sequence iterator(?) ● It works on Strings, lists, tuples, ● etc Example-> ● For <target> in <iterable>: ● statements
  26. 26. range/xrange They are used to generate and ● return integer sequence(?) Range(5) -> [0,1,2,3,4] ● Range(1,5) -> [1,2,3,4] ● Range(0,8,2) -> [0,2,4,6] ● Xrange is used as a memory ● efficient(?) alternative for range
  27. 27. break Used to terminate a loop ● If nested(?) it terminates the inner ● most loop Practically used for conditional loop ● termination with an if statement
  28. 28. continue Terminates the current iteration and ● executes next Practically used for conditional ● statements termination with an if statement
  29. 29. Some Helpful Functions Dir() ● Help() ●
  30. 30. Functions
  31. 31. What are functions? A Function is a group of statements ● that execute on request In Python Functions are Objects ● Defining a function -> ● def name(parameters): statement(s)
  32. 32. Parameters Types of parameters ● Mandatory Parameters Optional parameters Defaults values ● Be careful when default value is a ● mutable object
  33. 33. Example Def a(x,y=[]): ● y.append(x) print y print a(12) print a(34) What just happened here? ●
  34. 34. Namespace A namespace is an abstract container ● or environment created to hold a logical grouping of unique(!) identifiers or symbols <<MORE>> ●
  35. 35. Nested Functions Def statement inside a function ● defines a nested function Useful sometimes ● Use Of Class preffered ●
  36. 36. Functions (con) Return ● Return Type ● Some Examples ●
  37. 37. Modules
  38. 38. Modules What are modules? ● How to load modules ● Effect on namespace ● Important modules ● OS SYS –
  39. 39. How To Make Modules?
  40. 40. Y is this Important

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