Kebab file names

snippets/find-index.md

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+---
+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
+```