How to find array index closest to a given value using NumPy

Let’s say you have an 1D array like

arr = np.linspace(0, 10, 100)

and you wanted to find the array index where the value is closest to 8.5.

You can do this by first computing the absolute difference to 8.5:

np.abs(arr - 8.5)

and now using np.argmin to find the array index where the value is minimal (i.e. the index where the value of arr is closest to 8.5)

np.argmin(np.abs(arr - 8.5))