deep_flatten

snippets/deep_flatten.md

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+### deepFlatten
+
+Deep flattens a list.
+
+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.
+
+```python
+def spread(arg):
+    ret = []
+    for i in arg:
+        if isinstance(i, list):
+            ret.extend(i)
+        else:
+            ret.append(i)
+    return ret
+
+ def deep_flatten(arr):
+    result = []
+    result.extend(spread(list(map(lambda x : deep(x) if type(x) == list else x,arr))))
+    return result
+```
+
+```python
+deep_flatten([1, [2], [[3], 4], 5]) # [1,2,3,4,5]
+```