Python – Find Index containing String in List

Given a list, the task is to write a Python Program to find the Index containing String.

Example:

Input: [‘sravan’, 98, ‘harsha’, ‘jyothika’, ‘deepika’, 78, 90, ‘ramya’]

Output: 0 2 3 4 7

Explanation: Index 0 2 3 4 7 contains only string.

Method 1: Using type() operator in for loop

By using type() operator we can get the string elements indexes from the list, string elements will come under str() type, so we iterate through the entire list with for loop and return the index which is of type string.

0
2
3
4
7

Time Complexity: O(n)
Auxiliary Space: O(1)

Method 2: Using type() operator in List Comprehension

By using list comprehension we can get indices of string elements.

Syntax: [list.index(iterator) for iterator in list if(type(iterator) is str)]

Time Complexity: O(n)

Auxiliary Space: O(n)

Method 3: Using isinstance() function

['sravan', 98, 'harsha', 'jyothika', 'deepika', 78, 90, 'ramya']
[0, 2, 3, 4, 7]

The time and space complexity of all methods are:

Time Complexity: O(n)

Space Complexity: O(n)

Method 4: Using enumerate() function

['sravan', 98, 'harsha', 'jyothika', 'deepika', 78, 90, 'ramya']
0
2
3
4
7

Method 5: using isinstance() function 

['sravan', 98, 'harsha', 'jyothika', 'deepika', 78, 90, 'ramya']
0
2
3
4
7

Time complexity:O(n)

Auxiliary Space:O(n)