---
title: bifurcate
tags: list,intermediate
---

Splits values into two groups. 
If an element in `filter` is `True`, the corresponding element in the collection belongs to the first group; otherwise, it belongs to the second group.

Use list comprehension and `enumerate()` to add elements to groups, based on `filter`.

```py
def bifurcate(lst, filter):
  return [
    [x for i,x in enumerate(lst) if filter[i] == True],
    [x for i,x in enumerate(lst) if filter[i] == False]
  ]
```

```py
bifurcate(['beep', 'boop', 'foo', 'bar'], [True, True, False, True]) # [ ['beep', 'boop', 'bar'], ['foo'] ]
```
