#59EasyLists & Tuples· List Operations

List Operations: Remove Duplicates Preserving Order

Write `remove_duplicates(items)` that returns a new list containing each distinct value of `items` once, in the order of its first appearance. The input list must not be changed. `set(items)` alone is not enough, because a set does not remember order. Aim for a solution that looks at each item once.

Input format

`items`: a list of integers and/or strings.

Output format

A list with the duplicates removed.

Examples

Input: items = [3,1,3,2,1]

Output: [3,1,2]

The second 3 and the second 1 are dropped; the first occurrences keep their order.

Input: items = ["b","a","b","1",1]

Output: ["b","a","1",1]

The string "1" and the number 1 are different values.

Constraints

0 <= len(items) <= 10^5
Integers and strings are never equal to each other (1 and "1" are different values)

Study first

Lists and Tuples in Python

#python
#lists
#sets
#deduplication