# How to create a numpy array of all True or all False?

In Python, how do I create a numpy array of arbitrary shape filled with all True or all False?

numpy already allows the creation of arrays of all ones or all zeros very easily:

e.g. `numpy.ones((2, 2))`

or `numpy.zeros((2, 2))`

Since `True`

and `False`

are represented in Python as `1`

and `0`

, respectively, we have only to specify this array should be boolean using the optional `dtype`

parameter and we are done.

`numpy.ones((2, 2), dtype=bool)`

returns:

```
array([[ True, True],
[ True, True]], dtype=bool)
```

**UPDATE: 30 October 2013**

Since numpy version 1.8, we can use `full`

to achieve the same result with syntax that more clearly shows our intent (as fmonegaglia points out):

`numpy.full((2, 2), True, dtype=bool)`

**UPDATE: 16 January 2017**

Since at least numpy version 1.12, `full`

automatically casts results to the `dtype`

of the second parameter, so we can just write:

`numpy.full((2, 2), True)`

From: stackoverflow.com/q/21174961

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