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01. Create a list of integers from 1 to nE02. Access elements by positive and negative indexE03. Slice a list to get first and last three itemsE04. Append an item and extend a listE05. Insert and remove elements in a listE06. Find element index or return -1E07. Count occurrences of a value in a listE08. Reverse a list in-place and by slicingE09. Sort a list of numbers ascending and descendingE10. Convert between lists and tuplesE11. Interleave two lists element by elementM12. Flatten a single-level list of listsM13. Filter a list using a predicateM14. Map a function over a listM15. Rotate a list by k positionsM16. Get unique elements preserving orderM17. Partition a list by a conditionM18. Replace a sublist slice with another listM19. Group equal consecutive values into sublistsH20. Reconstruct a list from value-count tuplesH

Problem No 5

Insert and remove elements in a list

Easy

≈ 8 minute session

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Summary

Practice inserting an element at a specific position and removing the first occurrence of another element.

Problem statement

Write a function insert_and_remove(lst, index, value_to_insert, value_to_remove) that inserts value_to_insert into lst at the given index (like list.insert). After the insertion, remove the first occurrence of value_to_remove from the list if it exists. Return the modified list. Use the same list object (modify in-place) and handle indices that are negative or larger than the list length using Python's list.insert semantics.

Task

Implement a function that inserts a value at a given index and then removes the first occurrence of another specified value, returning the modified list.

Examples

Insert and remove

Input

insert_and_remove([1, 2, 4], 2, 3, 4)

Output

[1, 2, 3]

Explanation

Insert 3 at index 2 -> [1, 2, 3, 4], then remove the first 4 -> [1, 2, 3].

Input format

A function call: insert_and_remove(lst, index, value_to_insert, value_to_remove)

Output format

Return the modified list after insert and remove operations.

Constraints

Perform operations in-place. If value_to_remove is not present, return the list unchanged after insertion.

Samples

Sample input 0

insert_and_remove([], 0, 'a', 'b')

Sample output 0

['a']

Explanation 0

Inserting 'a' into an empty list then attempting to remove 'b' (not present) yields ['a'].

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