21 lines
530 B
Markdown
21 lines
530 B
Markdown
---
|
|
title: Find matching index
|
|
tags: list
|
|
cover: book-chair
|
|
firstSeen: 2020-03-10T22:38:48+02:00
|
|
lastUpdated: 2020-11-02T19:27:53+02:00
|
|
---
|
|
|
|
Finds the index of the first element in the given list that satisfies the provided testing function.
|
|
|
|
- Use a list comprehension, `enumerate()` and `next()` to return the index of the first element in `lst` for which `fn` returns `True`.
|
|
|
|
```py
|
|
def find_index(lst, fn):
|
|
return next(i for i, x in enumerate(lst) if fn(x))
|
|
```
|
|
|
|
```py
|
|
find_index([1, 2, 3, 4], lambda n: n % 2 == 1) # 0
|
|
```
|