Yingjie Lan wrote:
--- On Sat, 4/24/10, Steven D'Aprano <st...@remove-this-cybersource.com.au>
wrote:
From: Steven D'Aprano <st...@remove-this-cybersource.com.au>
Subject: Re: NameError: how to get the name?
To: python-list@python.org
Date: Saturday, April 24, 2010, 4:07 PM
On Sat, 24 Apr 2010 04:19:43 -0700,
Yingjie Lan wrote:
I wanted to do something like this:
while True:
try:
def fun(a, b=b, c=c): pass
except NameError as ne:
name = get_the_var_name(ne)
locals()[name] = ''
else: break
This won't work. Writing to locals() does not actually
change the local
variables. Try it inside a function, and you will see it
doesn't work:
I tried this, and it worked:
Python 2.6.1 (r261:67515, Feb 11 2010, 00:51:29)
[GCC 4.2.1 (Apple Inc. build 5646)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
while True:
... try: print a
... except: locals()['a']="HERE YOU ARE"
... else: break
...
HERE YOU ARE
Yes, but as Steven D'Aprano said, this won't work inside a function.
Try it.
Also if you find an instance where this works, you can't rely on the
behavior. If you RTM, you'll find this:
locals()ΒΆ <http://docs.python.org/library/functions.html#locals>
Update and return a dictionary representing the current local symbol
table. Free variables are returned by locals()
<http://docs.python.org/library/functions.html#locals> when it is
called in function blocks, but not in class blocks.
Note: The contents of this dictionary should not be modified;
changes may not affect the values of local and free variables used
by the interpreter.
Gary Herron
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