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Update some snippets

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Angelos Chalaris
2019-08-20 10:38:09 +03:00
parent 1c93753ade
commit f10d3f018b
6 changed files with 37 additions and 47 deletions
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snippets/difference_by.md
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@ -1,15 +1,16 @@
---
title: difference_by
tags: list
tags: list,function,intermediate
---
Returns the difference between two list, after applying the provided function to each list element of both.
Create a `set` by applying `fn` to each element in `b`, then use list comprehension in combination with fn on a to only keep values not contained in the previously created `set`.
Returns the difference between two lists, after applying the provided function to each list element of both.
Create a `set` by applying `fn` to each element in `b`, then use list comprehension in combination with `fn` on `a` to only keep values not contained in the previously created set, `_b`.
```py
def difference_by(a, b, fn):
b = set(map(fn, b))
return [item for item in a if fn(item) not in b]
_b = set(map(fn, b))
return [item for item in a if fn(item) not in _b]
```
```py