* Tim Chase:
Larry Hudson wrote:
But a minor rearrangement is simpler, and IMHO clearer:
if 'mystring' not in s:
print 'not found'
else:
print 'foundit'
print 'processing'
I've always vacillated on whether that would better be written as Larry
does, or as
if 'mystring' in s
print 'foundit'
print 'processing'
else:
print 'not found'
removing the "not" from the condition. I admit I choose one over the
other based on some gut-feeling aesthetic that I can't really nail
down. I think one of my major influencing factors revolves around the
negative "not" portion having one or two lines and the positive portion
having a large block of code. If the code-blocks are more equal in
size, I tend to use "if {positive}", but if the negative "not" section
is only 1-2 lines, I tend to do as Larry writes and make it harder to
miss by using "if {negative}". Otherwise the "if {positive}...else" can
end up sufficiently distant from the "if" that it's easy to miss.
Any thoughts on how others make the choice?
I think it spills over from the practice of checking preconditions first, e.g.
returning or raising exceptions or whatever.
This avoids silly n-level nesting of the main "normal case" part.
Cheers,
- Alf
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