# Python Absolute Value

### Software Development

### by: Ryan Ernst

The absolute value of a number is the non-negative value of a number without regard to its sign. This is often useful when you care more about the *size *of a value, you are calculating a delta from zero in either direction, or you are measuring something that is direction agnostic and only care about the magnitude.

In Python, to calculate the absolute value of a number you use the `abs`

function. This is a Python built-in function that is always available.

abs(0.1) # 0.1 abs(-0.1) # 0.1 abs(-5) # 5 abs(-1e3) # 1000.0

Sometimes though you might need to get the absolute value from every element in a list. In this case, you can use a list expansion and `abs`

:

[ abs(x) for x in [-1, 1, 2, -2] ] # [1, 1, 2, 2]

Maybe though you are using N-dimensional arrays (ndarrays) via NumPy, in that case, you can get the element-wise absolute value of a ndarray using `numpy.absolute`

:

import numpy as np np.absolute([ [-1,2], [2,-1] ]) # np.array([ [1, 2], [2, 1] ])

If you are using DataFrames in pandas, you can use the `pandas.DataFrame.abs`

method:

import pandas as pd df = pd.DataFrame({ 'a': [1, 2, -3], 'b': [-4, 5, -6], 'c': [7, 8, -9] }) # returns: # a b c # 0 1 4 7 # 1 2 5 8 # 2 3 6 9

Hopefully, this short little post has been helpful! If you have a topic you would like us to write about, or need help with a Python data project, please reach out at: tech@iq-inc.com!