# Easy way to test if each element in an numpy array lies between two values?

PythonNumpy## Python Problem Overview

I was wondering if there was a syntactically simple way of checking if each element in a numpy array lies between two numbers.

In other words, just as `numpy.array([1,2,3,4,5]) < 5`

will return `array([True, True, True, True, False])`

, I was wondering if it was possible to do something akin to this:

```
1 < numpy.array([1,2,3,4,5]) < 5
```

... to obtain ...

```
array([False, True, True, True, False])
```

I understand that I can obtain this through logical chaining of boolean tests, but I'm working through some rather complex code and I was looking for a syntactically clean solution.

Any tips?

## Python Solutions

## Solution 1 - Python

One solution would be:

```
import numpy as np
a = np.array([1, 2, 3, 4, 5])
(a > 1) & (a < 5)
# array([False, True, True, True, False])
```

## Solution 2 - Python

Another would be to use `numpy.any`

, Here is an example

```
import numpy as np
a = np.array([1,2,3,4,5])
np.any((a < 1)|(a > 5 ))
```

## Solution 3 - Python

You can also center the matrix and use the distance to 0

```
upper_limit = 5
lower_limit = 1
a = np.array([1,2,3,4,5])
your_mask = np.abs(a- 0.5*(upper_limit+lower_limit))<0.5*(upper_limit-lower_limit)
```

One thing to keep in mind is that the comparison will be symmetric on both sides, so it can do `1<x<5`

or `1<=x<=5`

, but not `1<=x<5`

## Solution 4 - Python

In multi-dimensional arrays you could use the `np.any()`

option suggested or comparison operators, while using `&`

and `and`

will raise an error.

##### Example (on multi-dim array) using comparison operators

```
import numpy as np
arr = np.array([[1,5,1],
[0,1,0],
[0,0,0],
[2,2,2]])
```

Now use `==`

if you want to check if the array values are inside a range, i.e A < arr < B, or `!=`

if you want to check if the array values are outside a range, i.e arr < A and arr > B :

```
(arr<1) != (arr>3)
> array([[False, True, False],
[ True, False, True],
[ True, True, True],
[False, False, False]])
(arr>1) == (arr<4)
> array([[False, False, False],
[False, False, False],
[False, False, False],
[ True, True, True]])
```