Python equivalent for Arduino's map function

Question

Arduino has a map() function that scales an integer value from one range to another. For example, you can take input from an 8-bit ADC sensor that ranges from 0–1024, and proportionally scale it to the range 0-100.

How would I do this in Python?

Answer 1

Like buran mentioned in the comments, the Arduino reference page for map() shows the full implementation, which can be copied almost verbatim into Python.

Here's the Arduino C++ code:

long map(long x, long in_min, long in_max, long out_min, long out_max) {
  return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
}

And here's what it would look like in Python. The only real gotcha is that / in Python returns a float even when both operands are integers; // is specifically integer division.

def map_range(x, in_min, in_max, out_min, out_max):
  return (x - in_min) * (out_max - out_min) // (in_max - in_min) + out_min

(I've also renamed it so it doesn't shadow Python's own map, which is something different entirely.)

Answer 2

Why don't you just divide by the original range max value and multiply by new range max-value?

new_value = (int) (my_value/max_value)*new_range_max

EDIT: if the original value is binary you can convert it to decimal by doing:

int(b, 2)  # Convert a binary string to a decimal int.

Reference: https://stackoverflow.com/a/13656358/11381650