*args and **opts oddities (?)

Dinu Gherman gherman at darwin.in-berlin.de
Thu Nov 29 09:47:49 CET 2001


Hi,

I'm trying to transform *args and **opts parameters and pretend
they were passed in some transformed way. What I find is an un-
expected phenomenon that makes me use indices in the code below
(in function transform1) to get the behaviour I want. Is there 
any good explanation for this?

Thanks,

Dinu


# unexpected result: lines (1) and (2) are not equal

def transform0(*args, **opts):
    print 't', args, opts
    return args, opts 

def call0(*args, **opts):
    print args, opts # (1)
    args, opts = transform0(args, opts)
    print args, opts # (2)


# result as expected, but in an unexpected way

def transform1(*args, **opts):
    print 't', args, opts
    return args[0], args[1] # ???

def call1(*args, **opts):
    print args, opts # (1)
    args, opts = transform1(args, opts)
    print args, opts # (2)


##    >>> call0('foo', 'bar', foobar=0)
##    ('foo', 'bar') {'foobar': 0}
##    t (('foo', 'bar'), {'foobar': 0}) {}
##    (('foo', 'bar'), {'foobar': 0}) {}
##    >>> 
##    >>> call1('foo', 'bar', foobar=0)
##    ('foo', 'bar') {'foobar': 0}
##    t (('foo', 'bar'), {'foobar': 0}) {}
##    ('foo', 'bar') {'foobar': 0}
##    >>>



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