How to compute a percentage increase/decrease multiplier in python without if statements

Question

I have a scenario in which the user enter a positive, 0, or negative value which represents a percentage increase, no change, or percentage decrease, respectively. Example: 2.5

Answer 1

if and else can actually be used in expressions on one line: x = a if b else c. You can't use elif, though, so you'll have to first refactor your code so it doesn't use them:

if U == 0:
   multiplier = 1
else:
    if U > 0:
       multiplier = U/100.0 + 1
    else:
       multiplier = (100 - (U * -1.0))/100.0

This reduces to

if U == 0:
   multiplier = 1
else:
   multiplier = U/100.0 + 1 if U > 0 else (100 - (U * -1.0))/100.0

Which reduces to

multiplier = 1 if U == 0 else (U/100.0 + 1 if U > 0 else (100 - (U * -1.0))/100.0)