Re: Forwarding keyword arguments from one function to another
Thnak you all. > In the future, explain "didn't work". > Wrong output? give actual (copy and paste) and expected. > Error message? give traceback (copy and paste). I will be careful. -- http://mail.python.org/mailman/listinfo/python-list
Re: Forwarding keyword arguments from one function to another
Ravi wrote: The following code didn't work: In the future, explain "didn't work". Wrong output? give actual (copy and paste) and expected. Error message? give traceback (copy and paste). -- http://mail.python.org/mailman/listinfo/python-list
Re: Forwarding keyword arguments from one function to another
On Sun, 2009-02-22 at 12:09 -0800, Ravi wrote:
> I am sorry about the typo mistake, well the code snippets are as:
>
> # Non Working:
>
> class X(object):
> def f(self, **kwds):
> print kwds
> try:
> print kwds['i'] * 2
> except KeyError:
> print "unknown keyword argument"
> self.g("string", kwds)
>
> def g(self, s, **kwds):
> print s
> print kwds
>
> if __name__ == "__main__":
> x = X()
> x.f(k = 2, j = 10)
>
>
> # Working One
>
> class X(object):
> def f(self, **kwds):
> print kwds
> try:
> print kwds['i'] * 2
> except KeyError:
> print "unknown keyword argument"
>self.g("string", **kwds)
>
> def g(self, s, **kwds):
> print s
> print kwds
>
> if __name__ == "__main__":
> x = X()
> x.f(k = 2, j = 10)
Same reasoning, though admittedly the error text is misleading.
This example can be simplified as:
def foo(x, **kwargs):
pass
>>> foo(1, {'boys': 5, 'girls': 10})
==> TypeError: foo() takes exactly 1 argument (2 given)
Again misleading, but the argument is the same (no pun intended).
However the following would have worked:
>>> foo(1, **{'boys': 5, 'girls': 10})
or
>>> foo(1, boys=5, girls=10)
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Re: Forwarding keyword arguments from one function to another
On Sun, 2009-02-22 at 11:44 -0800, Ravi wrote:
> The following code didn't work:
>
> class X(object):
> def f(self, **kwds):
> print kwds
> try:
> print kwds['i'] * 2
> except KeyError:
> print "unknown keyword argument"
> self.g("string", **kwds)
^^
This means call g() with kwds passed as keyword arguments.
> def g(self, s, kwds):
The method signature is not expecting keyword arguments.
> print s
> print kwds
>
> if __name__ == "__main__":
> x = X()
> x.f(k = 2, j = 10)
>
>
> However the following did:
>
> class X(object):
> def f(self, **kwds):
> print kwds
> try:
> print kwds['i'] * 2
> except KeyError:
> print "unknown keyword argument"
> self.g("string", **kwds)
>
> def g(self, s, **kwds):
^^
The method signature expects (optionally) keyword arguments.
> print s
> print kwds
>
> if __name__ == "__main__":
> x = X()
> x.f(k = 2, j = 10)
>
>
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Re: Forwarding keyword arguments from one function to another
I am sorry about the typo mistake, well the code snippets are as:
# Non Working:
class X(object):
def f(self, **kwds):
print kwds
try:
print kwds['i'] * 2
except KeyError:
print "unknown keyword argument"
self.g("string", kwds)
def g(self, s, **kwds):
print s
print kwds
if __name__ == "__main__":
x = X()
x.f(k = 2, j = 10)
# Working One
class X(object):
def f(self, **kwds):
print kwds
try:
print kwds['i'] * 2
except KeyError:
print "unknown keyword argument"
self.g("string", **kwds)
def g(self, s, **kwds):
print s
print kwds
if __name__ == "__main__":
x = X()
x.f(k = 2, j = 10)
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Re: Forwarding keyword arguments from one function to another
On Sun, 2009-02-22 at 11:44 -0800, Ravi wrote:
> The following code didn't work:
>
> def g(self, s, kwds):
> print s
> print kwds
This expects the function g to be called with the parameters "s" and
"kwds"
> def g(self, s, **kwds):
> print s
> print kwds
This expects to be passed the parameter "s", and various keyword
arguments, which will be put into the dict "kwds".
when you call
o.g("string",**kwds)
you are passing the parameter "string" as the first parameter, and then
a sequence of keyword arguments taken from kwds, which will be passed
separately.
This is what the second form expects, but not what the first one
expects.
Tim Wintle
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Forwarding keyword arguments from one function to another
The following code didn't work:
class X(object):
def f(self, **kwds):
print kwds
try:
print kwds['i'] * 2
except KeyError:
print "unknown keyword argument"
self.g("string", **kwds)
def g(self, s, kwds):
print s
print kwds
if __name__ == "__main__":
x = X()
x.f(k = 2, j = 10)
However the following did:
class X(object):
def f(self, **kwds):
print kwds
try:
print kwds['i'] * 2
except KeyError:
print "unknown keyword argument"
self.g("string", **kwds)
def g(self, s, **kwds):
print s
print kwds
if __name__ == "__main__":
x = X()
x.f(k = 2, j = 10)
Please explain
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