Basic Python Data Structures

Basic Python Data Structures

1. List

   • One of 4 built-in date sturcture
     • Changable
       • We can change the variable in side a List after the List has been defined
     • Ordered
       • Variable in List is well-ordered, which means, we can retrieve the variable by the order
       • a_list = ["a", "a", "b", "c" ] print(a_list[0]) will print "a"
     • Allow Duplicate element
       • We can add duplicate element in List
       • fruit = ["apple", "banana", "cherry", "apple", "cherry"]
   • a_list = ["a", "a", "b", "c" ]
   • Other function
     • len() will return the length of a list
       • thislist = ["a", "b", "c"] print(len(thislist)) will print 3
   • Data Type
     • string
     • int
     • boolean

2. Tuples

   • a_tuple = ("a", "b", "c")
   • Data Type
     • string
     • int
     • boolean
   • Other function
     • len() will return the length of a list
       • thistuple = ("a", "b", "c") print(len(thislist)) will print 3
   • One of 4 built-in date sturcture
     • Unchangable
       • We cannot change the variable in side a Tuple after the List has been defined
     • Ordered
       • Variable in List is well-ordered, which means, we can retrieve the variable by the order
       • a_tuple = ("a", "a", "b", "c" ) print(a_tuple[0]) will print "a"
     • Allow Duplicate element
       • We can define duplicate element in Tuple
       • fruit = ("apple", "banana", "cherry", "apple", "cherry")

3. Sets

   • a_set = {"a", "b", "c"}
   • One of 4 built-in date sturcture
     • Unordered
       • Unordered means that the items in a set do not have a defined order.
         • Python will print the element in a set in random order
     • Unchangable
       • We cannot change the element after a set is defined
       • But we can add new element
     • Not allow duplicate element
       • We cannot add duplicate element in Set
       • fruit = {"apple", "banana", "cherry", "apple", "cherry"} print(fruit)
         • {apple, banana, cherry}
   • Other function
     • len() will return the length of a list
       • thisset = {"a", "b", "c"} print(len(thislist)) will print 3
   • Data Type
     • int
     • boolean
     • string

4. Dictionaries

   • a_dict = {'name': 'Alexander', 'age': 35, 'sex': 'male', 'income': 1500}
   • Data Type
     • int
     • boolean
     • string
   • Other function
     • len() will print out the length of a dictonary
   • One of 4 built-in date sturcture
     • Changable
       • We can add, delete, or modify the element in dictonary
     • Orded*
       • Dictonary is an ordered Data Type and the order will not be changed
       • Unordered before Python 3.6
     • NOT allow the duplicate elements
       • Dictonary and not have two item with the same key
   • dict = {'a_key': 'some_variable'}