How can I tell if variable is defined
Mel
mwilson at the-wire.com
Tue Sep 22 16:48:09 EDT 2009
Grant Edwards wrote:
> On 2009-09-22, Brown, Rodrick <rodrick.brown at citi.com> wrote:
>
>> How could I do the following check in Python
>>
>> In Perl I could do something like if ((defined($a)) { ... }
>
> try:
> yourNameHere
> except NameError:
> print "undefined"
> else:
> print "defined"
This being Python, however, it can be fooled:
Python 2.6.2 (release26-maint, Apr 19 2009, 01:56:41)
[GCC 4.3.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> class A():
... def __repr__ (self):
... global b
... return b
...
>>> a = A()
>>> try:
... a
... except NameError:
... print "`a` is not defined"
...
`a` is not defined
Mel.
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