How can I use boolean array as index to filter a list?

For example:

```
>>> l = ['a','b','c']
>>> b = [True,False,False]
>>> l[b]
```

The result should be:

```
['a']
```

I know numpy support it but want to know how to solve in Python.

```
>>> import numpy as np
>>> l = np.array(['a','b','c'])
>>> b = np.array([True,False,False])
>>> l[b]
array(['a'],
dtype='|S1')
```