Python, can I iterate through a list within an if statement?

Question

I am trying to edit a str (myString) based on user input str (userInput). There are already a known set of subStrings that myString may or may not contain and are put into a list of str (namingConventionList) that, if any are used in myString should be replaced with userInput. If none of the set of naming conventions are used, I want the userInputadded to myString in a couple of different ways depending on if and where an underscore ("_") is. Is there a way to iterate through namingConventionList in an if statement?

        if myString.count(conv for conv in namingConventionList):
            myString= myString.replace(conv, userInput))
        elif userInput.startswith('_'):
            myString= '%s%s' % (name, userInput)
        elif userInputConvention.endswith('_'):
            myString= '%s%s' % (userInput, name)
        else:
            myString= '%s_%s' % (name, userInput)

Why not just have `for conv in namingConventionList:`, then have the `if` statement within that? — David Robinson, Apr 30 '15 at 03:31
I tried that, but I either have to put the elifs into the for loop which for every item in the list that doesn't appear in myString, the elifs do their thing which I don't want until the list is exhausted. — rasonage, Apr 30 '15 at 03:44

score 0 · Answer 1 · answered Apr 30 '15 at 03:37

0

This is how I might approach your problem:

for conv in namingConventionList:
    if conv in myString:
        myString = myString.replace(conv, userInput)
        break
else:
    if userInput.startswith('_'):
        myString= '%s%s' % (name, userInput)
    elif userInputConvention.endswith('_'):
        myString= '%s%s' % (userInput, name)
    else:
        myString= '%s_%s' % (name, userInput)

answered Apr 30 '15 at 03:37

Greg Hewgill

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This is the first time I've seen that [`for..else` construction](http://stackoverflow.com/questions/9979970/why-does-python-use-else-after-for-and-while-loops). Neat. – TigerhawkT3 Apr 30 '15 at 03:45

score 0 · Accepted Answer · answered Apr 30 '15 at 03:39

success = False
for conv in namingConventionList:
    if conv in myString:
        myString = myString.replace(conv, userInput)
        success = True

if not success:
    if userInput.startswith('_'):
        myString= '%s%s' % (name, userInput)
    elif userInputConvention.endswith('_'):
        myString= '%s%s' % (userInput, name)
    else:
        myString= '%s_%s' % (name, userInput)

Python, can I iterate through a list within an if statement?

2 Answers2