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I was going through ways of shortening a normal if else statement. One of the formats I found was to change this:

if x == 1:
    print("Yes")
else:
    print("No")

Into this:

print("Yes") if x == 1 else print("No")

Is the code above considered pythonic? Otherwise, what would be a pythonic way of shortening the if else statement?

I also tried using return instead of print. I tried

return total if x == 1 else return half

which resulted in an unreachable statement for the 2nd return. Is there a way of doing it that i'm not able to see?

Finally, I tried to use an else if instead of an else with the code, but that wouldn't work either. 

print(total) if x == 1 else print(half) if x == 2

The code above probably looks stupid logic-wise. Am I missing out on the proper format, or is it really not possible to do return and else if with this format?

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3 Answers 3

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9

The form

print("Yes") if x == 1 else print("No")

is not generally considered Pythonic, since ... if ... else ... is an expression and you're throwing away the value that the expression produces (always None). You can use print("Yes" if x == 1 else "No") which is Pythonic since the value of the conditional expression is used as the argument to print.

The form 

return total if x == 1 else return half

cannot work since return is a statement and must occur at the beginning of a logical line. Instead, use

return total if x == 1 else half

(which is parsed the same as return (total if x == 1 else half)).

The code 

 print(total) if x == 1 else print(half) if x == 2

wouldn't work either - the conditional expression is ... if ... else ..., i.e. each if must be paired with an else that follows it; your second if is missing the else clause; you could use

 print(total) if x == 1 else print(half) if x == 2 else print('something else')

Again, this wouldn't be considered very pythonic; but you could use

 print(total if x == 1 else half if x == 2 else 'something else')

not that it would be much better either.

Finally, if you're participating in a code golf

print("Yes" if x == 1 else "No")

can be shortened to

print(('No', 'Yes')[x == 1])

by using the fact that True == 1 and False == 0 and using these to index a tuple.

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3

Have you tried to use the ternary in the print itself ?

print("Yes" if x == 1 else "No")
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1 Comment

Yours is much shorter :)
1

A ternary if..else operates on expressions. return is a statement, not an expression. print() is an expression, but note the way you wrote it twice - you're printing regardless; it's just the expression you want to print that may vary.

print("Yes") if x == 1 else print("No")

The above is valid, but you don't need to have two references to the same function:

print("Yes" if x == 1 else "No")

The following is not valid, as you have multiple statements in there:

return total if x == 1 else return half

Again, operate on the expressions you'd like to work with:

return total if x == 1 else half

Now, a ternary is just that - ternary. It should have three parts, not four.

print(total) if x == 1 else print(half) if x == 2

In the above, you have four expressions:

  • print(total)
  • x == 1
  • print(half)
  • x == 2

That's too many. You can have one of the expressions be, itself, a larger expression, although it does always require an else (to be ternary):

print(total if x == 1 else half if x == 2 else 'Neither 1 nor 2.')

With more parentheses to show grouping:

print(total if x == 1 else (half if x == 2 else 'Neither 1 nor 2.'))

The expression in the inner parentheses above is an expression with a ternary operator itself, as well as an expression in a larger expression with a ternary operator.

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