30秒学会 Python 片段 – find_index.md

title: find_index
tags: list,beginner

Returns the index of the first element in the provided list that satisfies the provided testing function.

Use list comprehension, enumerate() and next() to return the index of the first element in lst for which fn returns True.

代码实现

def find_index(lst, fn):
  return next(i for i, x in enumerate(lst) if fn(x))

使用样例

find_index([1, 2, 3, 4], lambda n: n % 2 == 1) # 0