31 lines
599 B
Markdown
31 lines
599 B
Markdown
### deep_flatten
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Deep flattens a list.
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Use recursion. Use `list.extend()` with an empty array (`result`) and the spread function to flatten a list. Recursively flatten each element that is a list.
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```python
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def spread(arg):
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ret = []
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for i in arg:
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if isinstance(i, list):
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ret.extend(i)
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else:
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ret.append(i)
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return ret
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def deep_flatten(arr):
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result = []
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result.extend(
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spread(list(map(lambda x: deep(x) if type(x) == list else x, arr))))
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return result
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```
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```python
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deep_flatten([1, [2], [[3], 4], 5]) # [1,2,3,4,5]
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```
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