Showing posts with label Accessing elements of List in Python. Show all posts
Showing posts with label Accessing elements of List in Python. Show all posts

Sunday, October 25, 2020

Python Lists

Python has a builtin type name list. Lists values(elements/items) are enclosed within the square braces [] and separated by commas. Python lists are mutable and elements within the list can be replaced, removed. new elements can be inserted and appended. 


Python lists are heterogeneous, A list can contain a combination of different data types.

Here the list contains a integer, float and string

Accessing elements of List in Python:
Items/Elements of a list in python is accessed via index. List index starts from Zero, first element is accessed using zero, second element by 1 and so on. 
To access the elements from end the index starts from minus one (-1), last element in the list accessed using -1, second element from end is accessed using -2 and so on.To access fifth element from end use -5.

Accessing a List using Index Range:

Elements of a list can be accessed using the slicing operator : . Range of indexes can be specified in a list where to start and end.
list[startIndex : endIndex : Step]

elements of the list are displayed from start of Index till end of Index. Index element 6 is excluded while accessing using the range.


In the above example list1 we have passed list1[2:10:2], here the elements from the position 2 till position 10 with a step of 2. step determines the position of next element to be evaluated after current position element. Here the element at index position 2 is 3 next element to be evaluated is determined using the step size. step size is 2 so the next element is 5, next element is 7 and so on.. 

Step size is equal to 3, so every third element is evaluated from start position of index till end position of Index.




 



Operations on Python Dictionaries