On Sat, Mar 2, 2013 at 3:55 AM, 김용빈 <kyb...@gmail.com> wrote:
> why we bother with '{variable}'.format(variable=variable) ?
> can we just '{variable}.format()' ?
>
> if variable is exist, then assign it.
> if variable is not exist, then raise error
>
> I am not language expert. so sorry if this is not a good idea, or already
> discussed.
You're asking for a facility whereby variables magically get pulled
from the caller's scope. Let me put it to you another way:
def func1():
return foo + " world"
def func2():
foo = "Hello"
print("func1 returns: "+func1())
func2()
Will this work? If not, why not?
There are ways around this; you can, for instance, pass locals() to format():
'{variable}'.format(**locals())
But this is massive overkill and can unexpectedly expose a whole lot
more than you wanted (an issue if you accept a format string from an
untrusted source). Generally, it's best to be explicit. You can avoid
repeating the name so much by using positional parameters instead:
'{0}'.format(variable)
Of course, this has its own considerations. But at least it isn't magical. :)
ChrisA
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