Table of Contents

## Issue

Let’s assume we have a list like the following

[2.3, 1.02, 1.99, 0.99, 0.089, 0, 1.1, -1.1, -2.1]

We want to arrange the elements of this list based on their distance from target value equal to 1 in the following manner:

[0.99, 1.02, 1.1, 0.089, 1.99, 0, 2.3, -1.1, -2.1]

How to do that in python in one or two lines?

## Solution

##### python solution

Use `sorted`

with the absolute distance to target as key:

```
L = [2.3, 1.02, 1.99, 0.99, 0.089, 0, 1.1, -1.1, -2.1]
target = 1
out = sorted(L, key=lambda x: abs(x-target))
```

output: `[0.99, 1.02, 1.1, 0.089, 1.99, 0.0, 2.3, -1.1, -2.1]`

##### numpy solution

Compute the absolute distance and use `numpy.argsort`

:

```
L = [2.3, 1.02, 1.99, 0.99, 0.089, 0, 1.1, -1.1, -2.1]
target = 1
import numpy as np
a = np.array(L)
out = a[np.argsort(abs(a-target))].tolist()
```

output: `[0.99, 1.02, 1.1, 0.089, 1.99, 0.0, 2.3, -1.1, -2.1]`

Answered By – mozway

Answer Checked By – Marilyn (BugsFixing Volunteer)