CODEWITHSUNDEEP
pythonreturnconditional-statements
pyramidka
pyramidka

Reputation: 79

Is it possible in Python to make a one-liner with multiple IF and OR after RETURN statement?

I hope it's pretty clear what I wanna do with this function:

def this_one_operator(math_operator, num1, num2):
    return num1 * num2 if operator == "*" \
        or num1 / num2 if operator == "/" \
        or num1 + num2 if operator == "+" \
        or num1 - num2 if operator == "-"

Obviously, it doesn't work (SyntaxError: invalid syntax).

Sorry if I duplicate the question. I did my best to find here how to deal with that problem. Also, I appreciate any suggestion how to edit the question if it's not accurate.

Thanks.

Upvotes: 2

Views: 81

Answers (3)

PrestonH
PrestonH

Reputation: 566

This isn't pretty, but it works:

def this_one_operator(math_operator, num1, num2):
    return (operator == "/")*(num1/num2) + \
           (operator == "+")*(num1+num2) + \
           (operator == "-")*(num1-num2) + \
           (operator == "*")*(num1*num2)

The reason this works is that the boolean statements are equal to either 0 or 1, so multiplying them by the correct expression and summing the correct total will yield the right result.

Edit: Actually, this doesn't work as others have pointed out because the division operation may result in an undefined result.

Upvotes: 2

Dietrich Epp
Dietrich Epp

Reputation: 213378

Yes, but it's ugly.

return (x * y if operator == "*" else
        x / y if operator == "/" else
        x + y if operator == "+" else
        x - y if operator == "-" else
        None)

Alternatively:

import operator
OPERATORS = {
    '*': operator.mul,
    '/': operator.truediv,
    '+': operator.add,
    '-': operator.sub,
}

return OPERATOR[op](x, y)

Upvotes: 2

aghast
aghast

Reputation: 15310

Python has a value if condition else default ternary operation, which you could stack for this result. However, it's not very compact, and not very pythonic to be doing what you seem to want to do.

Instead, you might try:

import operator 

def binary_op(op, lopd, ropd):
    return { '/' : operator.floordiv,
             '*' : operator.mul,
             '+' : operator.add,
             '-' : operator.sub,
             '%' : operator.mod }[op](lopd, ropd)

Upvotes: 7

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