Robert Lummis wrote:
I want to write a function that I can use for debugging purposes that
prints the values of whatever list of object references it is given as
arguments, without knowing in advance how many object references it
will be called with or what they might be. For example, the call:
show(a,b,c) would output the values of the arguments like this:
a = 3
b = 'john'
c = 'Monday'
while show (x) would output (for example):
x = 3.14
of course displaying whatever the actual current values are. For a
collection object it would make sense to output just the first few
values.
To catch any number of arguments, you could do something like
def show(*args):
print args
but that gives you just a list of values, like [3, 'john', 'Monday']
Inside a function there is no way of finding out how the values ended up as
argument (or even whether a value has a name in the first place).
In general, a value may have several names, eg
a = []
b = a
or no names at all like
show(1)
In other words, what you want is not possible.
So within the 'show' function definition I have to somehow get a list
of the literal argument names it was called with and then use the
names as globals to get the values. How do I do that?
globals is not enough. What if I use show in a function?
If you really insist on using 'show()', you could do
show(('a', a), ('b', b), ('c', c))
with
def show(*args):
print '\n'.join(['%s = %s' % a for a in args])
but I think it is too complicated to type, compared to the 'print' statement
below.
If this can't be done but there is a completely different way to
achieve a similar result, what is it?
print "abc=", a, b, c
is what I always use.
I'm trying to learn python but it's a struggle because the
documentation is so dispersed. If there is a solution to this
question, what documentation could I have looked at to find it on my
own?
Dispersed?
Everything is documented at docs.python.org.
(your Python version may be the cause of your problems here though)
BTW I'm using python 3.01 if it matters.
That version is not ready for real use yet.
For learning Python you better use a 2.X version (2.6 is current).
Albert
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