fit "break IF condition" statement into one line

Question

I want to write a statement that breaks out of a for-loop if a certain condition is fulfilled, but in one line.

I know that this works:

for val in "string":
    if val == "i":
        break
    print(val)

and I know that this works:

value_when_true if condition else value_when_false

but when I run this piece of code I get a syntax error:

break if some_string[:5] == condition

Is there a way to write such a break condition in one line? Am I maybe doing something wrong?

Thanks!

You *can* put the `break` on the same line as the condition: `if val == "i": break`. — mkrieger1, Feb 11 '19 at 19:12

Olivier Melançon · Answer 1 · 2022-03-21T20:10:17.053

15

You cannot use a ternary expression because break is not an expression; it does not return a value.

Although, you can simply omit the line break like this:

for val in "string":
    if val == "i": break
    print(val)

edited Mar 21 '22 at 20:10

answered Feb 11 '19 at 19:09

Olivier Melançon

Also, this is not good practice enough to be part of the answer, but you can have fun and do `for val in takewhile('i'.__ne__, "string"): print(val)` – Olivier Melançon Feb 11 '19 at 19:21

score 3 · Answer 2 · answered Feb 11 '19 at 19:13

3

This worked for me:

for i in range(10):
  print(i)
  if i == 2: break

answered Feb 11 '19 at 19:13

Anadactothe

score 3 · Answer 3 · answered Feb 11 '19 at 19:16

There is no harm in writing below code

for val in "string":
    if val == "i":
        break

One-liners do not bring any good but all the operations are squashed in a single line which is hard to read.

value_when_true if condition else value_when_false This is only good if you have an expression. For example

x = 1 if True else 0

As break is not an expression it cannot be used in like above

if condition: break will break the loop. But again I would suggest to have your original code in place as it is more readable.

3 Answers3