The following code doesn't run but I hope you get what I
am trying to do.
class my_dict (dict):
def __getitem__ (self, key, crazy = False):
if crazy == True:
return 5 * self.get(key)
else:
return self.get(key)
foo = my_dict()
foo['a'] = 123
print foo['a']
print foo['a', crazy = True]
Is it somehow possible to overload __getitem__ with an additional
argument? Are there other possibilities to achiev this? Or is
the only solution to this to write a normal function call
`def my_get (self, key, crazy=False)'?
Ciao
Andreas
6  3589 
it seems like you can't do it exactly the way you're trying but you could do
this
def __getitem__(*ar gs):
if len(args) 1 and args[1]: return self.get(args[0]) * 5
return self.get(args[0])
then you would use it like
print foo['a']
print foo['a',True]
or even
print foo['a',"crazy"]
if you wanted.
or
crazy = True
print foo['a',crazy]
"Andreas Matthias" <am**@kabsi.atw rote in message
news:uf******** ****@buckbeak.h ogwarts...
The following code doesn't run but I hope you get what I
am trying to do.
class my_dict (dict):
def __getitem__ (self, key, crazy = False):
if crazy == True:
return 5 * self.get(key)
else:
return self.get(key)
foo = my_dict()
foo['a'] = 123
print foo['a']
print foo['a', crazy = True]
Is it somehow possible to overload __getitem__ with an additional
argument? Are there other possibilities to achiev this? Or is
the only solution to this to write a normal function call
`def my_get (self, key, crazy=False)'?
Ciao
Andreas
"inhahe" <in****@gmail.c omwrote in message
news:Ly******** ***********@big news3.bellsouth .net...
crazy = True
print foo['a',crazy]
just to clarify, you could use it like:
crazy = "I'm crazy" #this only has to be done once
print foo['a'] #not crazy
print foo['a',crazy] #crazy
(this may be totally unPythonic, i don't know.)
actually i ddin't think about the fact that you're overloading dict, which
can already take multiple values in getitem
so how about
class crazy: pass
and then in your dict class:
def __getitem__(*ar gs):
if args[-1] is crazy:
return self.get(args[:-1])*5
else:
return self.get(args)
and then
print foo[1,2] #not crazy
print foo[1,2,crazy] #crazy
I *think* that would work
"Andreas Matthias" <am**@kabsi.atw rote in message
news:uf******** ****@buckbeak.h ogwarts...
The following code doesn't run but I hope you get what I
am trying to do.
class my_dict (dict):
def __getitem__ (self, key, crazy = False):
if crazy == True:
return 5 * self.get(key)
else:
return self.get(key)
foo = my_dict()
foo['a'] = 123
print foo['a']
print foo['a', crazy = True]
Is it somehow possible to overload __getitem__ with an additional
argument? Are there other possibilities to achiev this? Or is
the only solution to this to write a normal function call
`def my_get (self, key, crazy=False)'?
Ciao
Andreas
in****@gmail.co m wrote:
actually i ddin't think about the fact that you're overloading dict, which
can already take multiple values in getitem
Oh, I didn't know that. I totally misinterpreted the error message.
so how about
class crazy: pass
and then in your dict class:
def __getitem__(*ar gs):
Apparently, args already is a tuple, so this should be:
def __getitem__(sel f, args):
Is this documented somewhere? I couldn't find it anywhere.
Thanks.
Ciao
Andreas
Apparently, args already is a tuple, so this should be:
def __getitem__(sel f, args):
Is this documented somewhere? I couldn't find it anywhere.
Don't know, I just assumed it would take multiple arguments because I knew I
had seen the form d[1,2] before, which incidentally is equivalent to
d[(1,2)] so I guess it makes sense that args is a tuple.
En Thu, 22 May 2008 20:38:39 -0300, Andreas Matthias <am**@kabsi.ate scribió: in****@gmail.co m wrote:
>actually i ddin't think about the fact that you're overloading dict, which
can already take multiple values in getitem
Oh, I didn't know that. I totally misinterpreted the error message.
>so how about
class crazy: pass
and then in your dict class:
def __getitem__(*ar gs):
Apparently, args already is a tuple, so this should be:
def __getitem__(sel f, args):
Is this documented somewhere? I couldn't find it anywhere.
No, that's not correct. First, there is nothing special with the arguments to dict.__getitem_ _ -- except that the syntax obj[index] provides a delimiter and it allows for obj[a,b] as a shortcut for obj[(a,b)] -obj.__getitem__ ((a,b))
You may use the *args notation in any function; it is always a tuple (a singleton, when you call the function with only one argument)
pydef foo(*args): print args
....
pyfoo(1)
(1,)
pyfoo(1,2)
(1, 2)
pyfoo((1,2))
((1, 2),)
Compare with:
pydef bar(arg): print arg
....
pybar(1)
1
pybar(1,2)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: bar() takes exactly 1 argument (2 given)
pybar((1,2))
(1, 2)
--
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