confusion in output of local and global variables in python

Question

I am a newbie to python and was experimenting with local and global variables. 'example1' produced the output '6,16,6 ', which is as expected.

x=6
def example1():
  print x
  print (x+10)
  print x  
example1()

In the 2nd example:

x=6
def example2():
   print x
   print (x+10)
print x  
example2()

I expected '6,16,6' as the o/p, but got '6,6,16 ' as the output. Can someone explain why this happened in 'example2()'?

(I was of the view that the 2nd 'print x' statement in 'example2' is referring to the global variable x (which equals 6), and hence, felt that '6,16,6' should be the output)

In the second code sample, the second print x is executed before example2. Hence 6,6,16. — Hans Then
– Hans Then, Commented Feb 17, 2016 at 7:13

user4312749 · Accepted Answer · 2016-02-17 07:13:28Z

1

In your second example, the first value of x will be 6. Then you are calling the method example2() which will firstly print x ( which is 6 ) and then x+10.

So the output will be:

6
6
16

For a better understanding, here is the order of execution for your program:

x=6
def example2():
   print x
   print (x+10)
print x  # this will be called first, so the first output is 6
example2() # then this, which will print 6 and then 16

answered Feb 17, 2016 at 7:13

user4312749

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3 Comments

sandra16 Over a year ago

This cleared the concept for me. Thanks a lot,Alex !

sandra16 Over a year ago

Sorry if it sounds rudimentary, but I'm not sure how to. Can you tell me ?

user4312749 Over a year ago

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Dark Matter · Accepted Answer · 2016-02-17 07:18:58Z

0

x=6
def example2():
   print x +"2nd call"
   print (x+10)
print x+" 1st call"  # This print gets call first
example2()

I think this explains.1st print gets called first as its out of function and before function too If u want output as 6,16,6 make chages as follow

x=6
def example2():
   print x
   print (x+10) 
example2()
print x

answered Feb 17, 2016 at 7:18

Dark Matter

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2 Comments

sandra16 Over a year ago

The first edit that you suggested is something I can use from now on, to understand the sequence of execution of my programs. Thank you for both the edits!

sandra16 Over a year ago

N.B: In line #3 and #5 of the 1st edit, explicit typecasting of integer into string would be needed, while printing the concatenation of an integer and string. Else, one would encounter an error. An easy way to do this would be : print str(x)+"2nd call"

Abhishek Kandel · Accepted Answer · 2022-05-28 21:38:38Z

0

Demonstrate Local and Global Variables.

Local variables are variables that are declared inside a function. Global variables are variables that are declared outside a function.

Program to demonstrate the use of Local and Global Variables.

global_var = 5                     #Global Variable
def add(a,b):
    local_var = a+b                #Local Variable
    print("The sum is",local_var)
    print("The global variable is",global_var)
add(10,20)

Output is:

The sum is 30
The global variable is 5

edited May 28, 2022 at 21:38

answered May 28, 2022 at 21:36

Abhishek Kandel

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