List methods in Python
Published: 2023-05-10 17:30:57


### An overview of string methods in Python
In this article, I will provide an overview of the most commonly used string methods in Python.
#### 1. append()
Used for appending and adding elements to the end of the List.
example:-
```
my_list = [1, 2, 3]
my_list.append(4)
print(my_list)  # Output: [1, 2, 3, 4]

```
#### 2. copy()
It returns a shallow copy of a list
example:-
```
my_list = [1, 2, 3]
new_list = my_list.copy()
print(new_list)  # Output: [1, 2, 3]

```
#### 3. clear()
  
This method is used for removing all items from the list.
example:-
```
my_list = [1, 2, 3] 
my_list.clear() print(my_list) # Output: []
```
#### 4. count()
These methods count the elements
example:-
```
my_list = [1, 2, 3, 2, 4, 2]
count = my_list.count(2)
print(count)  # Output: 3

```
### 5. extend() 
Adds each element of the iterable to the end of the List
example:-
```
my_list = [1, 2, 3]
my_list.extend([4, 5, 6])
print(my_list)  # Output: [1, 2, 3, 4, 5, 6]

```
#### 6. index()
Returns the lowest index where the element appears.
example:-
```
my_list = [1, 2, 3, 2, 4, 2]
index = my_list.index(2)
print(index)  # Output: 1

```
#### 7. insert()
Inserts a given element at a given index in a list.
example:-
```
my_list = [1, 2, 3, 4, 5]
my_list.insert(2, 'hello')
print(my_list)  # Output: [1, 2, 'hello', 3, 4, 5]

print("My name is {}, and I'm {} years old.".format(name, age))
 Output: "My name is Ankit, and I'm 25 years old."
 ```
####  8. pop()
Removes and returns the last value from the List or the given index value.
 example:-
 ```
my_list = [1, 2, 3, 4, 5]
removed_element = my_list.pop(2)
print(removed_element)  # Output: 3
print(my_list)  # Output: [1, 2, 4, 5]

```
#### 9. remove()
Removes a given object from the List.
example:-
```
my_list = [1, 2, 3, 4, 5]
my_list.remove(3)
print(my_list)  # Output: [1, 2, 4, 5]

```
#### 10. sort()
Sort a List in ascending, descending, or user-defined order
default is ascending and for reverse write 'reverse=True.
example :-
```
my_list = [3, 1, 4, 2, 5]
my_list.sort()
print(my_list)  # Output: [1, 2, 3, 4, 5]
my_list.sort(reverse=True) 
print(my_list) # Output: [5, 4, 3, 2, 1]
```
#### 11. List as Stack
Stack is data structure which works on last in first out principle.
List can be used as a stack by using the `append()` method to add elements to the top of the stack and the `pop()`
example:-
```
stack = []
stack.append('A')
stack.append('B')
stack.append('C')
print(stack)  # Output: ['A', 'B', 'C']
top = stack.pop()
print(top)  # Output: 'C'
print(stack)  # Output: ['A', 'B']

```
#### 12. List as Queue
Queue is data structure which work on last in last out principal.
A list can be used as a queue by using the `append()` method to add elements to the end of the queue and the `pop(0)`
example:-
```
queue = []
queue.append('A')
queue.append('B')
queue.append('C')
print(queue)  # Output: ['A', 'B', 'C']
front = queue.pop(0)
print(front)  # Output: 'A'
print(queue)  # Output: ['B', 'C']
```
Using the `pop(0)` method to remove elements from the beginning of a list can be inefficient for large lists, as it requires shifting all the remaining elements one position to the left. If you need to implement a more efficient queue, it's recommended to use the `deque` class from the `collections` module
example:-
```
from collections import deque

queue = deque()
queue.append('A')
queue.append('B')
queue.append('C')
print(queue)  # Output: deque(['A', 'B', 'C'])
front = queue.popleft()
print(front)  # Output: 'A'
print(queue)  # Output: deque(['B', 'C'])
```
### Referances
[python docs](https://docs.python.org/3/tutorial/datastructures.html)
[geeksForGeeks](https://www.geeksforgeeks.org/list-methods-in-python/)