How to condense if/else into one line in Python? [duplicate]

Answer 1

An example of Python's way of doing "ternary" expressions:

i = 5 if a > 7 else 0

translates into

if a > 7:
   i = 5
else:
   i = 0

This actually comes in handy when using list comprehensions, or sometimes in return statements, otherwise I'm not sure it helps that much in creating readable code.

The readability issue was discussed at length in this recent SO question better way than using if-else statement in python.

It also contains various other clever (and somewhat obfuscated) ways to accomplish the same task. It's worth a read just based on those posts.

Answer 2

There is the conditional expression:

a if cond else b

but this is an expression, not a statement.

In if statements, the if (or elif or else) can be written on the same line as the body of the block if the block is just one like:

if something: somefunc()
else: otherfunc()

but this is discouraged as a matter of formatting-style.

Answer 3

Only for using as a value:

x = 3 if a==2 else 0

or

return 3 if a==2 else 0

Answer 4

Python's if can be used as a ternary operator:

>>> 'true' if True else 'false'
'true'
>>> 'true' if False else 'false'
'false'