Python Ternary Operator Without else

JCB picture JCB · Aug 30, 2012 · Viewed 75.9k times · Source

Is it possible to do this on one line in Python?

if <condition>:
    myList.append('myString')

I have tried the ternary operator:

myList.append('myString' if <condition>)

but my IDE (MyEclipse) didn't like it, without an else.

Answer

Claudiu picture Claudiu · Aug 30, 2012

Yes, you can do this:

<condition> and myList.append('myString')

If <condition> is false, then short-circuiting will kick in and the right-hand side won't be evaluated. If <condition> is true, then the right-hand side will be evaluated and the element will be appended.

I'll just point out that doing the above is quite non-pythonic, and it would probably be best to write this, regardless:

if <condition>: myList.append('myString')

Demonstration:

>>> myList = []
>>> False and myList.append('myString')
False
>>> myList
[]
>>> True and myList.append('myString')
>>> myList
['myString']