# Python Indexing a sublist

PythonServer Side ProgrammingProgramming

In this tutorial, we are going to write a program that finds the index of a sublist element from the list. Let's see an example to understand it clearly.

## Input

nested_list = [[1, 2, 3], [4, 5], [6, 7, 8, 9]]

## Output

Index of 7:- 2
Index of 5:- 1
Index of 3:- 0

Let's see the simple and most common way to solve the given problem. Follow the given steps solve it.

• Initialize the list.
• Iterate over the list using the index.
• Iterate over the sub list and check the element that you want to find the index.
• If we find the element then print and break it

## Example

Live Demo

# initializing the lit
nested_list = [[1, 2, 3], [4, 5], [6, 7, 8, 9]]
# function to find the index
def index(element):
# initializing a flag for tracking the element
is_found = False
# iterating over the list
for i in range(len(nested_list)):
# iterating over the sub list
for j in range(len(nested_list[i])):
# cheking for the element
if nested_list[i][j] == element:
# printing the sub list index that contains the element
print(f'Index of {element}: {i}')
# changing the flag to True
is_found = True
# breaking the inner loop
break
# breaking the outer loop
if is_found:
break
# checking whether the element is found or not
if not is_found:
print("Element is not present in the list")
index(7)
index(5)
index(3)

## Output

If you run the above code, then you will get the following result.

Index of 7: 2
Index of 5: 1
Index of 3: 0

## Conclusion

If you have any queries regarding the tutorial, mention them in the comment section

Published on 07-Jul-2020 12:20:21