Confused: Newbie Function Calls

Pinku Surana suranap at gmail.com
Wed Aug 11 18:31:50 CEST 2010


On Aug 11, 12:07 pm, fuglyducky <fuglydu... at gmail.com> wrote:
> I am a complete newbie to Python (and programming in general) and I
> have no idea what I'm missing. Below is a script that I am trying to
> work with and I cannot get it to work. When I call the final print
> function, nothing prints. However, if I print within the individual
> functions, I get the appropriate printout.
>
> Am I missing something??? Thanks in advance!!!!
>
> ################################################
> # Global variable
> sample_string = ""
>
> def gen_header(sample_string):
>     HEADER = """
>     mymultilinestringhere
>     """
>
>     sample_string += HEADER
>     return sample_string
>
> def gen_nia(sample_string):
>     NIA = """
>     anothermultilinestringhere
>     """
>
>     sample_string += NIA
>     return sample_string
>
> gen_header(sample_string)
> gen_nia(sample_string)
>
> print(sample_string)

There are 2 problems with your program.

(1) If you want to use a global variable in a function, you have to
add the line "global sample_string" to the beginning of that
function.

(2) Once you do (1), you will get an error because you've got
sample_string as a global and a function parameter. Which one do you
want to use in the function? You should change the name of the
parameter to "sample" to solve that confusion.

Here's the result, which works for me:

sample_string = ""
def gen_header(sample):
    global sample_string
    HEADER = """
    mymultilinestringhere
    """
    sample_string = sample + HEADER
    return sample_string
def gen_nia(sample):
    global sample_string
    NIA = """
    anothermultilinestringhere
    """
    sample_string = sample + NIA
    return sample_string
gen_header(sample_string)
gen_nia(sample_string)
print(sample_string)



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