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i recently found that variables set in a function cannot be used in another function. so to make variables 'universal' i have to make them global variables?

and you do that buy stating them global, like this?

global [VARIABLE NAME]=[VALUE]

i have a feeling there is more to it.

Edited by ffs82defxp: n/a

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Last Post by vegaseat
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Yes that is the correct syntax for a global variable. How ever you can pass the value of variables around with things like return statements.

Votes + Comments
Answered the question directly. Offered an additional option.
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There are other options as well.

Make both functions methods of a class, and use class attributes to store relevant data.

Combine both functions into one.

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I don't know how to do any of that. lol

can you give me an example script snippet?

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Just a general example of functions and their parameters/arguments:

# example of passing parameters/arguments to and from functions

def get_data():
    """get the data from the user, from a file, or hard coded"""
    mydata = [1, 2, 3, 4]
    # return requested data to caller
    return mydata

def process_data(data=None):
    """this is also the main function of the program"""
    # if no data is passed, get it with this function call
    if not data:
        data = get_data()
    minimum_data = min(data)
    maximum_data = max(data)
    # pass the 2 needed data paramters/arguments to this function
    show_result(minimum_data, maximum_data)

def show_result(min_data, max_data):
    """display the result, needs 2 data paramters/arguments"""
    print( "result: min=%s  max=%s" % (min_data, max_data) )

# call the main function to start
# use default data via function get_data()
process_data()

# you can also supply the needed data to the main function
data = list("abcd")
process_data(data)

"""overall result -->
result: min=1  max=4
result: min=a  max=d
"""

Study it carefully! If you have questions, ask. Avoid global variables, as your program gets larger, they can easily create hard to find bugs.

Note: this code will work with Python2 or Python3

Edited by Ene Uran: p2 p3

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can i get a simpler example like with 3 functions and a simple task/concept

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can i get a simpler example like with 3 functions and a simple task/concept

The example is simple and you shoul try to understand it.
Break it down and ask question.

def get_data():
    """get the data from the user, from a file, or hard coded"""
    mydata = [1, 2, 3, 4]
    # return requested data to caller
    return mydata

print get_data()
'''my output-->
[1, 2, 3, 4]
'''

So this is how the first function work.
It take no argument and it has a standar list that get returned out off function.

Then we can look at the next function.

def process_data(data=None):
    """this is also the main function of the program"""
    # if no data is passed, get it with this function call
    if not data:
        #data = get_data()   #here come data from get_data() function.
        data = [1, 2, 3, 4]  #this is the same
    minimum_data = min(data)   #find minium value of a list
    maximum_data = max(data)   #find maxium value of a list
    # pass the 2 needed data paramters/arguments to this function
    #show_result(minimum_data, maximum_data)
    return( "result: min=%s  max=%s" % (minimum_data, maximum_data) )

l = [2,5,5,8]

#with no argument passed to function
print process_data()
'''my output-->
result: min=1  max=4
'''

#here we pass l as an argument
print process_data(l)
'''
my output-->
result: min=2  max=8
'''

Here i have made it so this function work alone,we simualte that data comes from first fuction.
And insted off useing show_result() we return data out off this function.

look at this and try to understan what going on,and ask question if something is unclear.

Edited by snippsat: n/a

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Here is a rather simple example of a number of functions working together from:
http://www.daniweb.com/forums/showthread.php?p=104853#post104853

def get_name():
    """this function only returns arguments"""
    first = "Fred"
    last = "Ferkel"
    return first, last

def show_name(name):
    """this function only receives an argument"""
    print( name )

def process_name(first, last):
    """this function reveives 2 arguments, returns 1 argument"""
    name = "Mr. " + first +" " + last
    return name

def main():
    """
    this function handles the other functions in order
    and deals with the arguments received and to be passed
    """
    first, last = get_name()
    name = process_name(first, last)
    show_name(name)

# start the program with this function call
main()
Votes + Comments
nice example
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Okay, i think i understand. Basically you pass a variable from one function to another by 'returning' it ?

And the next functions parameters are supposed to include the variable(s) name(s)?

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Okay, i think i understand. Basically you pass a variable from one function to another by 'returning' it ?

And the next functions parameters are supposed to include the variable(s) name(s)?

You pass variables as need as function arguments and/or returns.

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