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up vote 1 down vote favorite

I'm still learning python/jython, so sorry if I ask silly questions.

I have this for loop in java, but I have no idea how to code it in Python/Jython, since it insists using "in"...

for(String effectString : config.getStringList("string.list") {
// Do something

I tried:

for effectString = config.getStringList("string.list"):

and

for effectString in config.getStringList("string.list"):

but then I realised that I didn't defined effectString and, actually, effectString is config.getStringList("string.list")...

Thanks for explanation in advance, Amar!

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2  
Your last example is syntactically correct. –  Hyperboreus Nov 29 '13 at 19:02
    
In Python you don't need to define a variable before you use it in a for statement, so assuming config.getStringList("stringlist") is a generator of some sort, then you're all set –  MattDMo Nov 29 '13 at 19:03

3 Answers 3

up vote 0 down vote accepted

Your following syntax is correct if config.getStringList("string.list") returns a collection.

for effectString in config.getStringList("string.list"):

Syntax For loops

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It looks like it was my mistake, probably I missed something while testing that, anyway, thanks for explanation! –  user2971511 Nov 29 '13 at 19:29
up vote 0 down vote

You can use a for loop in python to iterate over iterables.

Iterables can be a list, dict, generator objects, etc.

For example

>>> for num in [1, 2, 3, 4]:
...     print num    
1
2
3
4
>>> my_nums = ("0", "1", "2")
>>> for num in my_nums:
...     print num
0
1
2
>>> my_classes = [int, float, abs, str]
>>> for cls in my_classes:
...     print cls
<type 'int'>
<type 'float'>
<built-in function abs>
<type 'str'>

For more details, have a look at the Python Docs.

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up vote 0 down vote

This syntax:

for effectString in config.getStringList("string.list"):

is correct. When using for loops in Python you implicitly create a local variable.

In some languages, for (i=0; i<10; i++) might be how a for loop would look. There, you explicitly initialize the variable i, to be used in the body of the loop. In Python, for something in iterable creates the local variable something.

It is also worth noting that the variable persists after the loop is finished:

>>> for i in range(10):
        pass
>>> print(i)
9
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