Iterate over *args? | 易学教程

问题

I have a script I'm working on where I need to accept multiple arguments and then iterate over them to perform actions. I started down the path of defining a function and using *args. So far I have something like below:

def userInput(ItemA, ItemB, *args):
    THIS = ItemA
    THAT = ItemB
    MORE = *args

What I'm trying to do is get the arguments from *args into a list that I can iterate over. I've looked at other questions on StackOverflow as well as on Google but I can't seem to find an answer to what I want to do. Thanks in advance for the help.

回答1:

Tho get your precise syntax:

def userInput(ItemA, ItemB, *args):
    THIS = ItemA
    THAT = ItemB
    MORE = args

    print THIS,THAT,MORE


userInput('this','that','more1','more2','more3')

You remove the * in front of args in the assignment to MORE. Then MORE becomes a tuple with the variable length contents of args in the signature of userInput

Output:

this that ('more1', 'more2', 'more3')

As others have stated, it is more usual to treat args as an iterable:

def userInput(ItemA, ItemB, *args):    
    lst=[]
    lst.append(ItemA)
    lst.append(ItemB)
    for arg in args:
        lst.append(arg)

    print ' '.join(lst)

userInput('this','that','more1','more2','more3')

Output:

this that more1 more2 more3

回答2:

>>> def foo(x, *args):
...   print "x:", x
...   for arg in args: # iterating!  notice args is not proceeded by an asterisk.
...     print arg
...
>>> foo(1, 2, 3, 4, 5)
x: 1
2
3
4
5

edit: See also How to use *args and **kwargs in Python (As referenced by Jeremy D and subhacom).

回答3:

If you do that :

def test_with_args(farg, *args):
    print "formal arg:", farg
    for arg in args:
        print "other args:", arg

Other information: http://www.saltycrane.com/blog/2008/01/how-to-use-args-and-kwargs-in-python/

回答4:

MORE = args

Or, directly:

for arg in args:
    print "An argument:", arg

回答5:

If your question is "how do I iterate over args", then the answer is "the same way you iterate over anything": for arg in args: print arg.

回答6:

Just iterate over args:

def userInput(ItemA, ItemB, *args):
    THIS = ItemA
    THAT = ItemB
    for arg in args:
        print arg

回答7:

First entry in: http://www.google.com/search?q=python+*args viz. http://www.saltycrane.com/blog/2008/01/how-to-use-args-and-kwargs-in-python/ should solve your problem,

来源：https://stackoverflow.com/questions/9569092/iterate-over-args

标签

python

arguments