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pythonlogic

Select a variable in a collection based on avoiding another

I have a collection of two variables

a = 2
b = 3
collection = [a, b]

I randomly choose one of them as my first variable:

first_variable = random.choice(collection)

Later, I want to select the other variable and store it in other_variable. How can I do this only by referring to first_variable and collection?

other_variable = something like "variable in collection that is not first_variable"

Remark: The collection will always contain two elements only. Thank you.

Solution

  • Straight-forward:

    a = 2
b = 3
collection = [a, b]

import random

first_variable = random.choice(collection)
other_variable = [item for item in collection if item != first_variable][0]

print(other_variable)

    Caution: this will obviously fail if a == b (it will produce an IndexError).