[vijaynag]

Hi, I am currently facing issues handling global variable. See the code below.

global var

def fun1:
var = appuifw.query(u"Enter your name","text")
print var


def fun2:
print var

def fun3:
print var

fun1()
fun2()
fun3()

------------------------

the value of var is not taken global and in fun2 and fun3 value of var is not printed.
If I try to use Var in fun2 and fun3, it says var is not defined.
please help

[ck.umraliya]

Originally Posted by vijaynag

the value of var is not taken global and in fun2 and fun3 value of var is not printed.
If I try to use Var in fun2 and fun3, it says var is not defined.
please help

Hello,

When a variable is to be used outside its scope, you need to declare it global like below.

def fun1():
    global var
    var = 5
    print var


def fun2():
    print var

def fun3():
    print var

fun1()
fun2()
fun3()

this will print var three times.

Regards,

[vijaynag]

Yes, it is working now. Thanks.

[gaba88]

Originally Posted by vijaynag

Yes, it is working now. Thanks.

hello vijaynag

its great that you solved your problem.
But then also i will advice you to have a glance on this wiki article about using variables in Python.

[marcelobarrosalmeida]

Hi

Just an aside.

When you make a assignment to var without global keyword, Python interpreter thinks this var is local and your other functions will not see any update to it since its value will be lost when the interpreter leaves func1 scope.

def func1():
    var = 2
    print var

var = 1
func1()
# output is 2

However, if you have just used var (no assignments), Python interpreter uses it as global. I mean:

def func1():
    print var

var = 1
func1()
#output is 1

So, global keyword may be omitted in this case.

But, how about the following code:

def func1():
    print var
    var = 2
    print var

var = 1
func1()
# output is "UnboundLocalError: local variable 'var' referenced before assignment"

In this case, Python does not treat first var as global, as you could expect, since it knows that func1 uses var some lines ahead. So, var is local and it was not assigned before (error) ! And, yes, Python process the function before executing it.

However, to avoid problems (explicit is better than implicit), put a big global at beginning.

Marcelo Barros