[FIXED] Insert calculated values between consecutive values in array

Issue

Let's say I have a simple array, like this one:

import numpy as np
a = np.array([1,2,3])

Which returns me, obviously:

array([1, 2, 3])

I'm trying to add calculated values between consecutive values in this array. The calculation should return me n equally spaced values between it's bounds.

To express myself in numbers, let's say I want to add 1 value between each pair of consecutive values, so the function should return me a array like this:

array([1, 1.5, 2, 2.5, 3])

Another example, now with 2 values between each pair:

array([1, 1.33, 1.66, 2, 2.33, 2.66, 3])

I know the logic and I can create myself a function which will do the work, but I feel numpy has specific functions that would make my code so much cleaner!

Solution

If your array is

import numpy as np

n = 2
a = np.array([1,2,5])

new_size = a.size + (a.size - 1) * n

x = np.linspace(a.min(), a.max(), new_size)
xp = np.linspace(a.min(), a.max(), a.size)
fp = a
result = np.interp(x, xp, fp)

returns: array([1. , 1.33333333, 1.66666667, 2. , 2.66666667, 3.33333333, 4. ])

If your array is always evenly spaced, you can just use

new_size = a.size + (a.size - 1) * n
result = np.linspace(a.min(), a.max(), new_size)

Answered By - sunnytown