如何在python / jython中执行此操作（用Java编码）？

Question

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!

Answer 1

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

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

Syntax For loops

Answer 2

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 .

Answer 3

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