Readability of if block

Question

I have a very long set of expressions in a if statement. But apparently I'm not allowed to split my if statement even when I'm not splitting the block with indentation for obvious python-reasons. I'm a total newbie in regard of python so I'm sorry if my question is annoying.

Ideally, I would like to have the if statement arranged this way:

if (expression1 and expression2) or
(
expression2 and
(
(expression3 and expression4) or 
(expression3 and expression5) or
(
expression4 and (expression6 or expression7)
)
):
    pass

Right now it's all in one line and not a lot of readable.

You _could_ wrap the entire thing in parens, but having that many expressions seems like a bit of a code smell to me. — Christian Dean, Mar 02 '17 at 18:24
try switch case; ref: http://stackoverflow.com/questions/11479816/what-is-the-python-equivalent-for-a-case-switch-statement — CSK, Mar 02 '17 at 18:25
Try changing it entirely. Make it a local variable, or several, to give a name to each of the conditions you are checking. Then you can break it up and make it shorter and more readable at the same time. — dsh, Mar 02 '17 at 18:28
Possible duplicate of [Python style: multiple-line conditions in IFs](http://stackoverflow.com/questions/181530/python-style-multiple-line-conditions-in-ifs) — MarcinKonowalczyk, Mar 02 '17 at 18:37
No matter what you do I doubt this series of expressions can become readable. — Dimitris Fasarakis Hilliard, Mar 02 '17 at 18:50

Jean-François Fabre · Answer 1 · 2017-03-02T18:35:19.923

3

You could use old-style backslashing for the first line, others don't need it because you're using parentheses:

if (expression1 and expression2) or \
(
expression2 and
(
(expression3 and expression4) or
(expression3 and expression5) or
(
expression4 and (expression6 or expression7)
)
)
):
    pass

note that your example had to be fixed because there was one closing parenthesis missing.

edited Mar 02 '17 at 18:35

answered Mar 02 '17 at 18:24

Jean-François Fabre

137,073
23
153
219

score 1 · Answer 2 · answered Mar 02 '17 at 18:25

1

Use a \ to have your expression on multiple lines, you can even ident it for more readability:

if (expression1 and expression2) or \
(expression2 and \
    (\
    (expression3 and expression4) or \
    (expression3 and expression5) or \
        ( \
         expression4 and (expression6 or expression7) \
         )\
         ):
    pass

answered Mar 02 '17 at 18:25

LoicM

1,786
16
37

3

that's because OP left a syntax error (omitting one closing parenthesis) just to mislead us. – Jean-François Fabre Mar 02 '17 at 18:34

score 1 · Accepted Answer · answered Mar 02 '17 at 18:25

Python has several ways to allow multi-line statements. In your case, you can simple wrap your entire if condition in parenthesis:

if ((expression1 and expression2) or
(
expression2 and
(
(expression3 and expression4) or 
(expression3 and expression5) or
(
expression4 and (expression6 or expression7)
)
)):
    pass

I should note however, having that many conditions in a single if statement seems like a bit of a code smell to me. Perhaps consider create helper functions to incapsulate some of the logic, or using multiple if statements.

score 0 · Answer 4 · answered Mar 02 '17 at 18:51

0

you could do this:

t1_2=(expression1 and expression2)
t3_4=(expression3 and expression4)
t3_5=(expression3 and expression5)
t6_7=(expression6 or expression7)
if test1 or(expression2 and (t3_4 or t3_5 or(expression4 and t6_7)):
    pass

answered Mar 02 '17 at 18:51

mikeLundquist

769
1
12
26

Readability of if block

4 Answers4