won't recognize functions in script

[Jeff Shannon]

In article <3cd9958d at news.cc.umr.edu>, Carl says...

> ... When I define
> functions python gives me 'NameError: name 'ascii_val' is not defined'
> 
> this piece of my code is this:
> 
> 
> print ch, ascii_val(ch)     # ch is just a character read from a file
> 
> def ascii_val(char):
>     # returns 1-26 for A-Z or 27 for a space
[...]

Functions must be defined before they are executed.  The snippet 
you posted will try to call ascii_val() before the interpreter 
has seen the 'def ascii_val(char)...' block.  That's where your 
name error is coming from.

Note that the def must come before the attempt to *execute* the 
function.  You can refer to ascii_val() within another function 
def, before it is defined, as long as that second function is not 
executed before the interpreter has processed ascii_val()'s def. 
So, for example, this will work:

def print_ascii(mystring):
    for ch in mystring:
        print ch, ascii_val(ch)

def ascii_val(char):
    # ...  (as defined above)

print_ascii("testing")

As a side note, you might wish to rename your function, because 
it's not returning an ascii value -- the ascii value is what is 
returned from ord(char), and then you're massaging that into 
something else.  Picking accurately descriptive function names 
will make your code *much* less confusing later on...  :)

-- 

Jeff Shannon
Technician/Programmer
Credit International