List in Python | Adding item | Removing item | Length of List | Frequency of an Element |Sorting of list |Conversion from list to string

Creating list

list1 = ["first","second","Third"]

print(list1)

list2 = [1,2,3,4]

print(list2)

Accessing elements of list

We should keep in mind that first element in a list is referred as the 0th element second as 1st and so on.

X = list1[0]

Y = list2[0]

print(X)

print(Y)

Changing element value

 list1[1] = "forth"  #position of element is given

list2[2] = 4

Adding element in list

At last of list

list1.append("fifth")

list2.append(5)

At specific position

listname.append(position,value)

list1.insert(3,"sixth")

list2.insert(3,6)

Removing element of a list

Using list.remove() 

this method remove element with its value

list1.remove("second")

list2.remove(2)

using pop() method

this method remove element at specified position.If position is not mentioned method will remove the last element.

list1.pop(2)

list2.pop(3)

list1.pop()

list2.pop()

using dlt method

this method remove element at specified position if position is not given it will delete the entire list

dlt list1[2]

dlt list2[3]

dlt list1  #deletes entire list and list will no longer exist

Getting position of element

x=list1.index("fifth")

print(x)

this method returns the position of a element.

Length of list

len(list1) method give the length of list or we can say it returns the number of element in a list

x = len(list1)

Frequency of a element in a list

Count returns the frequency of a element in a list.

list3 = [1,5,2,1,2,5,4]

x = list3.count(1)

print(x)

this will return 3 as the frequency of 1 in list is 3

y = list3.count(5)

print(y)

this will return 2 as frequency of 5 in the list is 2

Reversing a list

list3 = [1,5,2,1,2,5,4]

x = list3.reverse()

this method reverse the order of list.

Sorting of list

Sorting means arranging list in ascending or descending order

list3 = [1,5,2,1,2,5,4]

x = list3.sort()

print(x)

this will return list sorted in ascending manner.

Conversion of list to string

note that fr this conversion all element of a list should be string otherwise it will throw error.

list4 = ["h","e","l","l","o"]

X = ''.join(list4)

this will return hello in a string form.