python ? (conditional/ternary) operator for assignments

Will picture Will · Jun 22, 2010 · Viewed 68k times · Source

C and many other languages have a conditional (aka ternary) operator. This allows you to make very terse choices between two values based on the truth of a condition, which makes expressions, including assignments, very concise.

I miss this because I find that my code has lots of conditional assignments that take four lines in Python:

if condition:
    var = something
else:
    var = something_else

Whereas in C it'd be:

var = condition? something: something_else;

Once or twice in a file is fine, but if you have lots of conditional assignments the number of lines explode and, worst of all the eye is drawn to them.

I like the terseness of the conditional operator because it keeps things I deem un-strategic from distracting me when skimming the code.

So, in Python, are there any tricks you can use to get the assignment onto a single line to approximate the advantages of the conditional operator as I outlined them?

Answer

carl picture carl · Jun 22, 2010

Python has such an operator:

variable = something if condition else something_else

Alternatively, although not recommended (see @karadoc's comment):

variable = (condition and something) or something_else