5 ms·

For Python, a common idiom is to do this: condition and truecase or falsecase See "Boolean operations" and "Conditional expressions": http://docs.python.org/

For Python, a common idiom is to do this: condition and truecase or falsecase See "Boolean operations" and "Conditional expressions": http://docs.python.org/3/reference/expressions.html#boolean-operations http://docs.python.org/3/reference/expressions.html#boolean-...

Xixi 13y ago
This idiom is however out of flavor, unless you need to support python 2.4. Nowadays you would do this: truecase if condition else falsecase
- binarycrusader 13y ago
  Heh; my "age" is starting to show. The first version of Python I learned was Python 2.4 and it was only a few years ago I finally moved to 2.6. Skipping 2.7 and moving to 3.3+ soon. Personally, I prefer the brevity of the older syntax, but to each his own. However, I understand the "ternary" expression was added because the older syntax was error-prone: http://mail.python.org/pipermail/python-dev/2005-September/056510.html http://mail.python.org/pipermail/python-dev/2005-September/0... http://www.python.org/dev/peps/pep-0308/ http://www.python.org/dev/peps/pep-0308/
jes5199 13y ago
ah! I've been trying to write Python lately (I'm more of a Rubyist) and the internet suggested: truecase if condition else falsecase which is so inside-out that it hurts. It didn't occur to me to use the boolean style - I guess I think of that as a perl idiom, and assumed that it would get sneered at in py-land
- comex 13y ago
  It was mostly used before the creation of the ternary operator in Python 2.5.
- pyre 13y ago
  I've never seen: $CONDITION && $TRUE_CASE || $FALSE_CASE used as a Perl idiom in lieu of: $CONDITION ? $TRUE_CASE : $FALSE_CASE I can't claim to have worked with Perl much prior to Perl 5.6/5.8 though, so it may have been an older idiom (though I doubt it as one of Perl's influences was Awk, which also has a C ternary operator, IIRC). That said, using truthy/falsey values in Python doesn't seem super common. I surprised a couple of interviewers by doing that while implementing some tree manipulation functions.
cheald 13y ago
This is how you do it in Lua, as well, since it doesn't have a ternary operator.

Xixi 13y ago

This idiom is however out of flavor, unless you need to support python 2.4. Nowadays you would do this: truecase if condition else falsecase

binarycrusader 13y ago
Heh; my "age" is starting to show. The first version of Python I learned was Python 2.4 and it was only a few years ago I finally moved to 2.6. Skipping 2.7 and moving to 3.3+ soon. Personally, I prefer the brevity of the older syntax, but to each his own. However, I understand the "ternary" expression was added because the older syntax was error-prone: http://mail.python.org/pipermail/python-dev/2005-September/056510.html http://mail.python.org/pipermail/python-dev/2005-September/0... http://www.python.org/dev/peps/pep-0308/ http://www.python.org/dev/peps/pep-0308/

jes5199 13y ago

ah! I've been trying to write Python lately (I'm more of a Rubyist) and the internet suggested: truecase if condition else falsecase which is so inside-out that it hurts. It didn't occur to me to use the boolean style - I guess I think of that as a perl idiom, and assumed that it would get sneered at in py-land

comex 13y ago
It was mostly used before the creation of the ternary operator in Python 2.5.
pyre 13y ago
I've never seen: $CONDITION && $TRUE_CASE || $FALSE_CASE used as a Perl idiom in lieu of: $CONDITION ? $TRUE_CASE : $FALSE_CASE I can't claim to have worked with Perl much prior to Perl 5.6/5.8 though, so it may have been an older idiom (though I doubt it as one of Perl's influences was Awk, which also has a C ternary operator, IIRC). That said, using truthy/falsey values in Python doesn't seem super common. I surprised a couple of interviewers by doing that while implementing some tree manipulation functions.

cheald 13y ago

This is how you do it in Lua, as well, since it doesn't have a ternary operator.