19 lines
403 B
Markdown
19 lines
403 B
Markdown
---
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title: intersection
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tags: list,beginner
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---
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Returns a list of elements that exist in both lists.
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Create a `set` from `a` and `b`, then use the built-in set operator `&` to only keep values contained in both sets, then transform the `set` back into a `list`.
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```py
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def intersection(a, b):
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_a, _b = set(a), set(b)
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return list(_a & _b)
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```
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```py
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intersection([1, 2, 3], [4, 3, 2]) # [2, 3]
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```
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