Python Programming List method full details

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Day 1:   Python learn to start on 6/1/2021

Topic: Some Method of the list:

Method  Name

# 1. To add element on the list or in other also we can use append( ) and extend( ) 

1. .append( ) 

we can use .append( ) in two ways 

i.

code:

list = [1, 4, 9, 'girl', True ]

list2 = ["hari", False, 45, 77] 

list.append(list2)

print(list)

Result:

[1, 4, 9, 'girl', True, ['hari', False, 45, 77]]

To add multi-element we use extend() which we will discuss below.

ii.

Simply we use append( ) method for add only one element example:

Code:

list = [1, 4, 9, 'girl', True ]

list.append(45)

print(list)

 

.extend( )

We use extend( ) method for adding multi-element. Example given below:

Code:

list = [1, 4, 9, 'girl', True ]

list2 = ["hari", False, 45, 77] 

list.extend(list2)

print(list)

Result:

[1, 4, 9, 'girl', True, 'hari', False, 45, 77]

 

we don't use extend( ) for adding one element on a list if we do that error occur:

example:

Code:

list = [1, 4, 9, 'girl', True ]

list.extend(45)

print(list)

   

Result:

Traceback (most recent call last):

  File "d:\New folder\second.py", line 2, in <module>

    list.extend(45)

TypeError: 'int' object is not iterable

• insert( )

We use insert( ) to insert the element in a specified position simply use list.insert(pos, elmnt)

were, pos. = the position where you want to add the element and elmnt. = element where you can give the element want to insert.

for example:

a = [2, 4, 8, 10, 12]

a.insert(2,6)

print(a)

Result:

[2, 4, 6, 8, 10, 12]

Note:-we count from 0 1 2 3 4....

#2. To remove the element we use .clear( ), pop( ), remove( ), and .del( )

• clear( )

we use clear( ) method to remove all the element from the list

example:

code:

list = [1, 4, 9, 'girl', True ]

list.clear()

print(list)

 

Result:

[ ]

 

• pop( )

We can use the pop( ) method to remove a particular element

example:

code:

fruits = ['apple', 'bannana', 'charry', 'kiwi']

fruits.pop(1)

print(fruits)

Here fruits are the name of the list, inside the square bracket there is a thing on the list. we use pop(1) to remove the second element of the list, where 1 is the position of the element.

note: in python, we start counting from 0 so, in the above example 1 = the second element 

Result:

['apple', 'charry', 'kiwi']

If we don't write the position in pop( ) method then it automatically removes the last element. list

for example:

fruits = ['apple', 'bannana', 'charry', 'kiwi']

fruits.pop()

print(fruits)

Result:

['apple', 'bannana', 'charry']

• remove( )

We use remove( ) method to remove the element from list but we only remove one element in remove()

code:

fruits = ['apple', 'bannana', 'charry', 'kiwi']

fruits.remove("kiwi")

print(fruits)

Result:

['apple', 'bannana', 'charry']

Day 2:

Today we are going to learn other method use in list: like copy( ), count( ), index( ), reverse( ) and  sort( ).

• copy( )

We use copy( ) method to copy list for example:

fruits = ['apple', 'bannana', 'charry', 'kiwi']

fruits2=fruits.copy()

print(fruits2)

Result:

['apple', 'bannana', 'charry', 'kiwi']

• count( )

We use the count() method to count the number of the element in the list for example:

a = [34, 45, 93, 34, 65, 34, 93, 34]

print(a.count(34))

Result:

4

• index( )

To find the position of the element we use index () method for example:

fruits = ['apple', 'banana', 'cherry']

x = fruits.index("cherry")

print(x)

Result:

2

• reverse( )

We can use reverse( ) to reverse the list for example:

fruits = ['apple', 'banana', 'cherry']

fruits.reverse()

print(fruits)

 Result:

['cherry', 'banana', 'apple']

• sort( )

We use sort( ) to arrange the element of list in order for example

cars = ['Ford', 'BMW', 'Volvo']

cars.sort()

print(cars)

 

Result:

['BMW', 'Ford', 'Volvo']

We also arrange in different ways by using a function in sort( ) for example

# A function that returns the length of the value:

def myFunc(e):

  return len(e)

cars = ['Ford', 'Mitsubishi', 'BMW', 'VW']

cars.sort(reverse=True, key=myFunc)

print(cars)

Result:

['Mitsubishi', 'Ford'', 'BMW', 'VW']