|
How do you set a global variable in a function?
Python Questions and Answers
(Continued from previous question...)
How do you set a global variable in a function?
Did you do something like this?
x = 1 # make a global
def f():
print x # try to print the global
...
for j in range(100):
if q>3:
x=4
Any variable assigned in a function is local to that function. unless it is specifically declared global. Since a value is bound to x as the last statement of the function body, the compiler assumes that x is local. Consequently the print x attempts to print an uninitialized local variable and will trigger a NameError.
The solution is to insert an explicit global declaration at the start of the function:
def f():
global x
print x # try to print the global
...
for j in range(100):
if q>3:
x=4
In this case, all references to x are interpreted as references to the x from the module namespace.
(Continued on next question...)
Other Interview Questions
| 