CODEWITHSUNDEEP
python
tkbx
tkbx

Reputation: 16275

Why aren't my globals global?

I have the following lines at the beginning of my script: 

global lotRow
global lotCol

Then, later on, I set lotRow and lotCol as strings using a function. Then, even later, I do the following:

getIDFromAxes(int(lotRow), int(lotCol))

This gives me:

    getIDFromAxes(str(lotRow), str(lotCol))
NameError: global name 'lotRow' is not defined

I have the def() print the "lot" strings at the end to be sure they are set, and I still can't access them for some reason.

Upvotes: 0

Views: 90

Answers (2)

Filip Roséen
Filip Roséen

Reputation: 63797

You'll need to use the keyword global when inside the function that is trying to access your global variables, otherwise it will look for a local definition - which of course doesn't exist.

global global_variable


def set_var ():
  global global_variable

  global_variable = 3

def print_var ():
  global global_variable

  print int(global_variable)


set_var   ()
print_var ()

global_variable = 321

print_var ()

output:

3
321

Upvotes: 2

icktoofay
icktoofay

Reputation: 129001

global statements don't go at the beginning of a script; they go inside of a function that needs access to global variables. So rather than:

global x
x = 0

def increment_x():
    x += 1
    return x

You'll need to use:

x = 0

def increment_x():
    global x
    x += 1
    return x

Upvotes: 4

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