Python-equivalent of short-form "if" in C++

Question

Is there a way to write this C/C++ code in Python? a = (b == true ? "123" : "456" )

It's called a ternary-if, by the way. http://en.wikipedia.org/wiki/%3F:, http://en.wikipedia.org/wiki/Ternary_operation — GManNickG, Nov 06 '09 at 09:16

score 254 · Accepted Answer · answered Nov 06 '09 at 09:16

254

a = '123' if b else '456'

answered Nov 06 '09 at 09:16

SilentGhost

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This ternary operator was introduced in Python 2.5. – David Webb Nov 06 '09 at 09:19
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For future reference, here's the Python documentation for the conditional expression: http://docs.python.org/reference/expressions.html#boolean-operations – Greg Hewgill Nov 06 '09 at 09:25
What does that mean? – Nov 08 '16 at 21:59

score 25 · Answer 2 · answered May 02 '12 at 22:55

25

While a = 'foo' if True else 'bar' is the more modern way of doing the ternary if statement (python 2.5+), a 1-to-1 equivalent of your version might be:

a = (b == True and "123" or "456" )

... which in python should be shortened to:

a = b is True and "123" or "456"

... or if you simply want to test the truthfulness of b's value in general...

a = b and "123" or "456"

? : can literally be swapped out for and or

answered May 02 '12 at 22:55

jdi

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I should note that the and..or approach here can backfire on you if the "123" value were actually an empty string or evaluates to a false value. The if..else is a bit safer. – jdi Apr 29 '14 at 19:56

score 21 · Answer 3 · answered May 02 '12 at 22:39

21

My cryptic version...

a = ['123', '456'][b == True]

answered May 02 '12 at 22:39

Socram

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That was one of the old approaches before the single-line if statement was possible, right? Kind of like how you can do it with logical: `True and "foo" or "bar" ` – jdi May 02 '12 at 22:49

score -1 · Answer 4 · edited May 03 '12 at 06:52

-1

See PEP 308 for more info.

edited May 03 '12 at 06:52

Jason Sundram

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answered Nov 06 '09 at 09:17

ghostdog74

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Whilst this may theoretically answer the question, [it would be preferable](//meta.stackoverflow.com/q/8259) to include the essential parts of the answer here, and provide the link for reference. – clickbait Aug 04 '18 at 03:44
This is not an elaborative answer, I dont see it helpful – JeanCarlos Chavarria Jul 30 '19 at 22:34

Python-equivalent of short-form "if" in C++

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