Python List and It's Functions
A list in Python is an ordered collection of items, which can be of any data type, including numbers, strings, and other objects. Lists are defined using square brackets [] and items are separated by commas:
fruits = ['apple', 'banana', 'cherry']
numbers = [1, 2, 3, 4, 5]
Lists in Python are mutable, which means you can add, remove, or modify items after the list has been created. For example:
# Adding an item to the end of a list
fruits.append('orange')
print(fruits) # ['apple', 'banana', 'cherry', 'orange']
# Removing an item from a list
fruits.remove('banana')
print(fruits) # ['apple', 'cherry', 'orange']
# Modifying an item in a list
numbers[2] = 10
print(numbers) # [1, 2, 10, 4, 5]
You can access items in a list by using an index, which starts at 0 for the first item and increases by 1 for each subsequent item:
print(fruits[0]) # 'apple'
print(fruits[1]) # 'cherry'
List() Function
list() function is used to create a list or typecast other types of iterable object as list. list function takes as argument iterable for create a new list.
a = list((10,20,30,59,29))
print(a) # [10, 20, 30, 59, 29]
a = (39,29,12,8,99)
print(list(a)) # [39, 29, 12, 8, 99]
a = list(("hello World"))
print(a) # ['h', 'e', 'l', 'l', 'o', ' ', 'W', 'o', 'r', 'l', 'd']Accessing List Items Using Their Index
List item can be access using their index . index startswith 0 and endswith size-1 .
a = [10,20,30,59,29]
print(a[0]) # 10
print(a[1]) # 20
print(a[2]) # 30
print(a[3]) # 59
print(a[4]) # 29
Modifying List
we can modify the list and change .
a = [10,20,30,59,29]
a[2] = 200
a[4] = 77
print(a[0]) # 10
print(a[1]) # 20
print(a[2]) # 200
print(a[3]) # 59
print(a[4]) # 77
List methods(functions) in Python
| Method | Uses |
|---|---|
| count() | Returns the number of elements in a list as specified |
| clear() | Removes all the elements from the list |
| copy() | Returns a copy of list |
| extend() | Add the elements in a list at the end |
| index() | Returns the index of the item at given position |
| insert() | Add an item at the specified position |
| append() | Add an element at the end of the list |
| pop() | Remove an last item of list or at the specified position |
| remove() | Removes the specified item |
| reverse() | Reverses the order of list |
| sort() | Sorts the list |
List Pop() Methods
remove the last item or from specified position.
a = [10,29,93,-82,2,87]
print(a.pop()) # 87
print(a.pop(4)) # 2List Append() Methods
Add item at the ends of the list
a = [10,29,93,-82,2,87]
a.append(55)
print(a) # [10, 29, 93, -82, 2, 87, 55]List Count() Methods
count how many item present in a list as specified item.
a = [10,29,93,-82,2,87]
print(a.count(20)) # 0
print(a.count(29)) # 1List Clear() Method
clear all item from the list return as empty
a = [10,29,93,-82,2,87]
a.clear()
print(a) # []List Remove() Method
remove an item from the list
a = [10,29,93,-82,2,87]
a.remove(-82)
print(a) # [10, 29, 93, 2, 87]List Reverse() Method
reverse the list
a = [10,29,93,-82,2,87]
a.reverse()
print(a) # [87, 2, -82, 93, 29, 10]