Question

Maybe this question has been asked before, but I couldn’t find it.
I am trying to implement something that determines what range a given value is in. In this example, x may be any real number.

def f(x):
    if x < 0.1:
        do_something_1()
    elif 0.1 <= x < 1:
        do_something_2()
    elif 1 <= x < 10:
        do_something_3()
    elif x >= 10:
        do_something_4()

…you get the idea.

I’ve seen plenty of examples of dictionaries replacing switch statements in Python, but I’ve always understood dictionaries as indexing discrete values.

I find it hard to believe that the if-elif-else chain is the best solution in this situation. Does anyone know of a better one?

Answer 1

Use the bisect package to find the index where the value lies, and then call the appropriate function. In your example:

import bisect

def f(x):
    funcs = [do_something_1, do_something_2, do_something_3, do_something_4]
    funcs[bisect.bisect_left([.1, 1, 10], x)]()