Python: Finding elements in an array that fall within a range

Question

I have an array and an integer

import numpy as np

a = np.array([1,2,3,4])
b = 3

I would like to find all elements in a that are within +-diff of b. If diff=1 then I can do this using

d = np.where( (a == b - 1) | (a == b) | (a == b + 1) )
vals = a[d]

But what if diff = 2, or is undetermined and I want to create a function that has diff as an input?

I'm sure there must be a far more efficient and flexible way to code this than I have found.

I'm using Python 3.5

llllllllll · Accepted Answer · 2018-02-15 17:00:41Z

2

You can use inequality expression:

a[ (b + diff >= a) & (a >= b - diff) ]

answered Feb 15, 2018 at 17:00

llllllllll

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1 Comment

Thank you, sometimes the obvious is hard to see!