Scaling a number between a certain range to that of another in python

Question

Is there a method by which a number between the range of lets say (a, b) can be scaled to a different range of lets say (p, q)?

In my case, I have a number between in the range of 0 to 1 i.e (0, 1) and wanna scale it such that it lies in the range of -1 to 1 i.e.(-1, 1).

Example -:

# 1 will remain 1 if scaled.
scale(1, (0, 1), (-1, 1)) # => Returns 1
# 0.5 will be scaled to 0.
scale(0.5, (0, 1), (-1, 1)) # => Returns 0
# 0 will be scaled to -1.
scale(0, (0, 1), (-1, 1)) # => Returns -1

I was able to find a few related threads on -: Based on mathematical formula and does not mention any pythonic way of doing so and secondly I am not able to distinguish between the upper and lower limits and max(x), min(x)

What kind of range is `(1, -1)`??? Should be `(min, max)`, not `(max, min)`. — goodvibration, Dec 20 '20 at 08:06
Does this answer your question? [Convert a number range to another range, maintaining ratio](https://stackoverflow.com/questions/929103/convert-a-number-range-to-another-range-maintaining-ratio) — Abrogans, Dec 20 '20 at 08:12

score 1 · Accepted Answer · answered Dec 20 '20 at 08:08

1

Try this:

def scale(x, srcRange, dstRange):
    return (x-srcRange[0])*(dstRange[1]-dstRange[0])/(srcRange[1]-srcRange[0])+dstRange[0]

Of course, each range must be given in the form of (min, max).

In your example, one of the ranges is given the form of (max, min).

answered Dec 20 '20 at 08:08

goodvibration

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Yup sry I did not notice that I will edit the range to min, max – typedecker Dec 20 '20 at 08:46
Yes this works Thanks for the answer can you explain a little bit on how this works? – typedecker Dec 20 '20 at 08:49

Scaling a number between a certain range to that of another in python

1 Answers1