Dax Feliz - 4 months ago 37

Python Question

I want to figure out how to remove nan values from my array. It looks something like this:

`x = [1400, 1500, 1600, nan, nan, nan ,1700] #Not in this exact configuration`

I'm relatively new to python so I'm still learning. Any tips?

Answer

If you're using numpy for your arrays, you can also use

```
x = x[numpy.logical_not(numpy.isnan(x))]
```

Equivalently

```
x = x[~numpy.isnan(x)]
```

[Thanks to chbrown for the added shorthand]

**Explanation**

The inner function, `numpy.isnan`

returns a boolean/logical array which has the value `True`

everywhere that `x`

is not-a-number. As we want the opposite, we use the logical-not operator, `~`

to get an array with `True`

s everywhere that `x`

**is** a valid number.

Lastly we use this logical array to index into the original array `x`

, to retrieve just the non-NaN values.