[Tutor] Change dictionary value depending on a conditional statement.

[Terry Carroll]

I don't think I saw anyone point this out yet, but, using "list" as a
variable name is a bad idea, because it hides the list method.

>>> x = list("abcdefg")
>>> x
['a', 'b', 'c', 'd', 'e', 'f', 'g']

This works.  You now have a variable named "x" that is a list.

>>> list = list("hijklmnop")
>>> list
['h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p']

This works, sort of.  You now have a variable named "list" that is a list. 
But since you reused the name "list," it can no longer point to the list 
function.

>>> y = list("qrstuv")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'list' object is not callable

And so this fails.




On Tue, 12 Feb 2008, Norman Khine wrote:

> Thank you all, very nice.
> 
> Steve Willoughby wrote:
> > Kent Johnson wrote:
> >> Try
> >>    list.append({'id': 'name', 'link': ('YY','XX')[total > 0]})
> > 
> > I'd caution against that, though.  It's clever and cute, sure, but the 
> > meaning of it is obfuscated enough to be unpythonic because [total > 0] 
> > as a subscript doesn't mean anything unless you know you're taking 
> > advantage of an implementation detail that booleans are 0 for false and 
> > 1 for true.  No matter how reliable that fact may be, I don't think that 
> > value should be stuck into a numeric context like that.
> > 
> >> Or, in Python 2.5,
> >>    list.append({'id': 'name', 'link': ('XX' if total > 0 else 'YY')})
> > 
> > This is much more clear, and would IMHO be fine.
> > 
> > 
> > 
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> > 
> 
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