Python equivalent for a C expression

Question

Dear fellow C programmers, sorry to ask such a basic question to you, but what would be the equivalent of this:

val = dim == 0 ? 1 : S(dim) * pow(radius * 0.5, dim) / dim

in Python? I am wrapping some C code and I need to know what is going on in this line in order to compare with the Python results...

Should't this be addressed "Dear fellow **Python** programmers" ? (I know plenty C programmers, including myself, that know zilch about python). — WhozCraig, Aug 24 '13 at 19:02
possible duplicate of [Ternary conditional operator in Python](http://stackoverflow.com/questions/394809/ternary-conditional-operator-in-python) — dawg, Aug 24 '13 at 19:11

Rohit Jain · Accepted Answer · 2013-08-24T19:08:20.603

8

From Python 2.5 onwards, the conditional expression - a ? b : c can be written like this:

b if a else c

So, your expression will be equivalent to:

val = 1 if dim == 0 else S(dim) * pow(radius * 0.5, dim) / dim

edited Aug 24 '13 at 19:08

answered Aug 24 '13 at 19:02

Rohit Jain

JackCColeman · Answer 2 · 2013-08-24T20:52:27.993

1

For most languages, including Python(without braces(?) and correct indentation), the following C statement:

val = (dim == 0) ? 1 : S(dim) * pow(radius * 0.5, dim) / dim;

can be written as something like: (minor differences are language specific, etc.)

if (dim == 0)
   {
      val = 1;
   } else {
      val = S(dim) * pow(radius * 0.5, dim) / dim;
   }

However, the Python code given in a previous answer is very nice!

edited Aug 24 '13 at 20:52

answered Aug 24 '13 at 19:36

JackCColeman

thank you to show how the compact expression would look like in an `if-else` statement in `C`... – Saullo G. P. Castro Aug 24 '13 at 20:23
@SaulloCastro, not a problem. Overtime you might come to like the "conditional expression" for quick one line data entry. – JackCColeman Aug 24 '13 at 20:52

2 Answers2