SlideShare a Scribd company logo

A quick python_tour

•
•
C
cghtkh

This document provides an overview of the Python programming language. It describes that Python is an object-oriented, dynamically typed language that can be used for scripting, rapid prototyping, text processing, web applications, games, databases, and more. It then demonstrates Python's built-in data types like integers, floats, strings, lists, tuples, and dictionaries. Finally, it shows Python's control structures like conditionals, loops, functions, classes and objects.

Related slideshows

Python programming : Inheritance and polymorphism
Python programming : Inheritance and polymorphismPython programming : Inheritance and polymorphism
Python programming : Inheritance and polymorphism
 
Python programming : Classes objects
Python programming : Classes objectsPython programming : Classes objects
Python programming : Classes objects
 
An introduction to scala
An introduction to scalaAn introduction to scala
An introduction to scala
 
1 of 17
Download to read offline
A Quick Python Tour Brought to you by
What is Python? • Programming Language created by Guido van Rossum • It has been around for over 20 years • Dynamically typed, object-oriented language • Runs on Win, Linux/Unix, Mac, OS/2 etc • Versions: 2.x and 3.x
What can Python do? • Scripting • Rapid Prototyping • Text Processing • Web applications • GUI programs • Game Development • Database Applications • System Administrations • And many more.
A Sample Program function def greetings(name=’’): ’’’Function that returns a message’’’ if name==’’: docstring msg = ”Hello Guest. Welcome!” else: msg = ”Hello %s. Welcome!” % name return msg variable indentation >>> greetings(“John”) # name is ‘John’ ‘Hello John. Welcome!’ comment >>> greetings() ‘Hello Guest. Welcome!’
Python Data Types • Built-in types  int, float, complex, long • Sequences/iterables  string  dictionary  list  tuple
Built-in Types • Integer >>> a = 5 • Floating-point number >>> b = 5.0 • Complex number >>> c = 1+2j • Long integer >>> d = 12345678L
String • Immutable sequence of characters enclosed in quotes >>> a = “Hello” >>> a.upper() # change to uppercase ‘HELLO’ >>> a[0:2] # slicing ‘He’
List • Container type that stores a sequence of items • Data is enclosed within square brackets [] >>> a = [“a”, “b”, “c”, “d”] >>> a.remove(“d”) # remove item “d” >>> a[0] = 1 # change 1st item to 1 >>> a [ 1, “b”, “c” ]
Tuple • Container type similar to list but is immutable • More efficient in storage than list. • Data is enclosed within braces () >>> a = (‘a’, ‘b’, ‘c’) >>> a[1] ‘b’ >>> a[0] = 1 # invalid >>> a += (1, 2, 3) # invalid >>> b = a+(1,2,3) # valid, create new tuple
Dictionary • Container type to store data in key/value pairs • Data is enclosed within curly braces {} >>> a = {“a”:1, “b”:2} >>> a.keys() [‘a’, ‘b’] >>> a.update({‘c’:3}) # add pair {‘c’:3} >>> a.items() [(‘a’, 1), (‘c’, 3), (‘b’, 2)]
Control Structures • Conditional  if, elif, else - branch into different paths • Looping  while - iterate until condition is false  for - iterate over a defined range • Additional control  break - terminate loop early  continue - skip current iteration  pass - empty statement that does nothing
if, else, elif • Syntax: • Example: if condition1: x=1 statements y=2 if x>y: [elif condition2: print “x is greater.” statements] elif x<y: [else: print “y is greater.” statements] else: print “x is equal to y.” • Output: y is greater.
while • Syntax: • Example: while condition: x= 1 statements while x<4: print x x+=1 • Output: 1 2 3
for • Syntax: • Example: for item in sequence: for x in “abc”: statements print x • Output: a b c
Function • A function or method is a group of statements performing a specific task. • Syntax: • Example: def fname(parameters): def triangleArea(b, h): [‘’’ doc string ‘’’] ‘’’Return triangle area‘’’ area = 0.5 * b * h statements return area [return expression] • Output: >>> triangleArea(5, 8) 20.0 >>> triangleArea.__doc__ ‘Return triangle area’
class and object • A class is a construct that represent a kind using methods and variables. An object is an instance of a class. • Syntax: • Example: class ClassName: class Person: [class documentation] def __init__(self, name): class statements self.name = name def introduce(self): return “I am %s.” % self.name • Output: >>> a = Person(“John”). # object >>> a.introduce() ‘I am John.’
End of Tour This is just a brief introduction. What is next? • Read PySchools Quick Reference • Practice the online tutorial on PySchools Have Fun!

More Related Content

A quick python_tour

  • 1. A Quick Python Tour Brought to you by
  • 2. What is Python? • Programming Language created by Guido van Rossum • It has been around for over 20 years • Dynamically typed, object-oriented language • Runs on Win, Linux/Unix, Mac, OS/2 etc • Versions: 2.x and 3.x
  • 3. What can Python do? • Scripting • Rapid Prototyping • Text Processing • Web applications • GUI programs • Game Development • Database Applications • System Administrations • And many more.
  • 4. A Sample Program function def greetings(name=’’): ’’’Function that returns a message’’’ if name==’’: docstring msg = ”Hello Guest. Welcome!” else: msg = ”Hello %s. Welcome!” % name return msg variable indentation >>> greetings(“John”) # name is ‘John’ ‘Hello John. Welcome!’ comment >>> greetings() ‘Hello Guest. Welcome!’
  • 5. Python Data Types • Built-in types  int, float, complex, long • Sequences/iterables  string  dictionary  list  tuple
  • 6. Built-in Types • Integer >>> a = 5 • Floating-point number >>> b = 5.0 • Complex number >>> c = 1+2j • Long integer >>> d = 12345678L
  • 7. String • Immutable sequence of characters enclosed in quotes >>> a = “Hello” >>> a.upper() # change to uppercase ‘HELLO’ >>> a[0:2] # slicing ‘He’
  • 8. List • Container type that stores a sequence of items • Data is enclosed within square brackets [] >>> a = [“a”, “b”, “c”, “d”] >>> a.remove(“d”) # remove item “d” >>> a[0] = 1 # change 1st item to 1 >>> a [ 1, “b”, “c” ]
  • 9. Tuple • Container type similar to list but is immutable • More efficient in storage than list. • Data is enclosed within braces () >>> a = (‘a’, ‘b’, ‘c’) >>> a[1] ‘b’ >>> a[0] = 1 # invalid >>> a += (1, 2, 3) # invalid >>> b = a+(1,2,3) # valid, create new tuple
  • 10. Dictionary • Container type to store data in key/value pairs • Data is enclosed within curly braces {} >>> a = {“a”:1, “b”:2} >>> a.keys() [‘a’, ‘b’] >>> a.update({‘c’:3}) # add pair {‘c’:3} >>> a.items() [(‘a’, 1), (‘c’, 3), (‘b’, 2)]
  • 11. Control Structures • Conditional  if, elif, else - branch into different paths • Looping  while - iterate until condition is false  for - iterate over a defined range • Additional control  break - terminate loop early  continue - skip current iteration  pass - empty statement that does nothing
  • 12. if, else, elif • Syntax: • Example: if condition1: x=1 statements y=2 if x>y: [elif condition2: print “x is greater.” statements] elif x<y: [else: print “y is greater.” statements] else: print “x is equal to y.” • Output: y is greater.
  • 13. while • Syntax: • Example: while condition: x= 1 statements while x<4: print x x+=1 • Output: 1 2 3
  • 14. for • Syntax: • Example: for item in sequence: for x in “abc”: statements print x • Output: a b c
  • 15. Function • A function or method is a group of statements performing a specific task. • Syntax: • Example: def fname(parameters): def triangleArea(b, h): [‘’’ doc string ‘’’] ‘’’Return triangle area‘’’ area = 0.5 * b * h statements return area [return expression] • Output: >>> triangleArea(5, 8) 20.0 >>> triangleArea.__doc__ ‘Return triangle area’
  • 16. class and object • A class is a construct that represent a kind using methods and variables. An object is an instance of a class. • Syntax: • Example: class ClassName: class Person: [class documentation] def __init__(self, name): class statements self.name = name def introduce(self): return “I am %s.” % self.name • Output: >>> a = Person(“John”). # object >>> a.introduce() ‘I am John.’
  • 17. End of Tour This is just a brief introduction. What is next? • Read PySchools Quick Reference • Practice the online tutorial on PySchools Have Fun!