Tuple, List and Dictionary

This series will feature short notes on Python topics. The idea is to reinforce my learning through "note taking".

Tuple

• Tuple is just like an array. It is immutable, and holds a sequence of values. However, unlike a C/C++ array, a tuple can store values of mixed types. An example:
  

    myTuple = ("Python", "PHP", "Ruby", 3.1428, 2009, "Django")

  
  


• Just like a string, a tuple can be indexed, sliced and concatenated with another tuple. When called on a tuple, the len() function returns the total number of elements in the tuple.
  

  totElements = len(myTuple)
  print totElements # It prints 6

  
  

List

• A list is like a C/C++ dynamic array. Elements can be added, deleted and sorted


• Just like a tuple, it can store data of mixed types.


• A list is enclosed in square brackets. For example:
  

  myList = ["Python", "PHP", "Ruby", "Perl", ('a', 'e', 'i', 'o', 'u')]
  emptyList = [] # this creates an empty list

  
  


• All the tuple operations are applicable to lists

Dictionary

• A dictionary is like a hash table in other programming languages. It stores data as key-value pairs.


• A dictionary is enclosed in curly braces.


• The key must be an immutable data type, i.e. string or tuple. For example,
  

   
  myDict = {"name" : "Charles Martel", "occupation" : "Palace Mayor, coup leader", "country" : "France"}
  emptyDict = {} # This creates an empty dictionary