More info on one line if-else statements in python

Question

Putting an if-elif-else statement on one line? did not give me enough information figure out my problem. I want to turn

if pointer == 0:
    quit(print("ERROR:POINTER VALUE < 0"))
else:
    pointer -=1

into a one line if statement so I can put it in an exec() statement. Please elaborate on the info provided in the linked question

`'quit(print("ERROR:POINTER VALUE < 0")) if pointer == 0 else pointer -=1'` — Ramiro Rocha, Aug 10 '17 at 17:47
The link you referenced will only work for assigning 2 (or more) different values to a variable. I think @Nick Frost's answer should work out — MikeChav, Aug 10 '17 at 17:49

score 0 · Accepted Answer · answered Aug 10 '17 at 17:48

0

exec doesn't actually need its argument to be in one line. You can pass it a multi-line string.

exec('if a:\n print("true")\nelse:\n print("false")')

answered Aug 10 '17 at 17:48

Nick Frost

That was actually one of the things I tried. It did not work as I intended – Ramiro Rocha Aug 10 '17 at 23:22

score 0 · Answer 2 · answered Aug 10 '17 at 17:48

0

You can use the ternary operator.

Read up on the wikipedia entry here - https://en.wikipedia.org/wiki/%3F:

Basically, it's a way to write a conditional when you have only two possible results for boolean comparison. It's great for very short lines.

For example:

x = 5 if True else x = 4
x = 1 if x == 0 else y = 10/x

In your case, it may not be the best decision, as your line will grow pretty long.

answered Aug 10 '17 at 17:48

blake

will `'quit(print("ERROR:POINTER VALUE < 0")) if pointer == 0 else pointer -=1'` work? – Ramiro Rocha Aug 10 '17 at 23:20
Your best bet might be to wrap all of the meat into a function. Then call the function in exec() – blake Aug 11 '17 at 12:50

2 Answers2