Use comparison statement as parameter in function to then pass as condition in while loop

Question

Imagine I had some function like this:

def func(condition):
    while condition:
        pass

Is there any way that I can pass a comparison as condition, for example func(50 > x) , but then instead of it executing as while False (x would be some value under 50), it does while 50 > x (I want to do something like x += 1, so the loop stops eventually)? I want to do this because I will have the same function in two different situations, and each of them has a while loop, but the condition has to be different from one another. What I did until now is pass another argument into func , so def func(condition,situation) , and then I would do while 50 > x if situation == 1 else True . However, I believe the way I am trying to do it, would be faster, because in the way I have been doing it thus far, after each loop, not only would 50 > x or True have to be evaluated again, but also if situation == 1 .

This is about what I want to do

limit = 50
start = 0

def func(condition)
    while condition:
        pass
        start += 1

# once I need the function like this, once I need it with True, so the loop runs forever in that case
func(limit > start)

func(True)

Answer 1

Maybe by passing a comparison function and the desired parameters? Something like this:

comparison_a = lambda x, y: x > y
comparison_b = lambda x, y: x <= y

(assuming your second condition is something like x <= y ) This creates two lambda (for simplification) functions that perform the desired comparison with the parameters x and y

Then you create your function as:

def func(comparison, start, limit):
    while comparison(start, limit):
        start += 1

And call it as:

limit = 50
start = 30

func(comparison_a, 50, 30)

Optionally, you could use the operator module, which implements python operators as functions. For the greater than operator you have operator.gt . As an example:

import operator

limit = 50
start = 30

func(operator.gt, 50, 30)

Answer 2

While I would advise against dynamic parameters like this, you could use the built-in eval method, which takes a string of Python and evaluates it inline.

def func(condition: String):
    while eval(condition):
        pass