Question

Ok! Basically, I have a variable being declared in one function, and I would like to use that variable in another function. I do not want to pass parameters, because I feel like there would be a simpler way to do this. This is my code:

#!/usr/bin/python

#import os
import time
print ("Hello and welcome to Pygame!")
time.sleep(1)
print ("Would you like to load? (\"Y/N\")")

def LON():
    loadOrNew = raw_input()

    if loadOrNew == "N":
        hp = 100
        strhp = str(hp)
        lvl = 1
        strlvl = str(lvl)
        atk = 5
        stratk = str(atk)
        defn = 2
        strdefn = str(defn)
        fout = open("pygame.dat", "w")
        fout.write (strhp) 
        fout.write("\n")
        fout.write(strlvl)
        fout.write("\n")
        fout.write(stratk)
        fout.write("\n")
        fout.write(strdefn)
        fout.close()
        FIRSTPLAY()
        return

    if loadOrNew == "Y":
        fin = open("pygame.dat", "r")
        hpstr = fin.readline()
        lvlstr = fin.readline()
        atkstr = fin.readline()
        defstr = fin.readline()
        hp = int(float(hpstr))
        lvl = int(float(lvlstr))
        atk = int(float(atkstr))
        defn = int(float(defnstr))
        fin.close()
        return

    if loadOrNew != "Y" and loadOrNew != "N":
        print("Im sorry, what?")
        LON()
        return

    return

def SAVE():
    fout = open("pygame.dat", "w")
    fout.write(hp)
    fout.write(lvl)
    fout.write(atk)
    fout.close(defn)
    return


def FIRSTPLAY():
    print("man/woman?")
    gender = raw_input()
    if gender != "man" and gender != "woman":
        print("Not valid gender.")
        FIRSTPLAY()

    print("KING - ")    
    print(" Young " + gender + ", you are herby my knight!")
    time.sleep(1)
    print(" My daughter, princess PYTHON, has been captured!")
    time.sleep(1)
    print(" You are to find her, and relieve this world of her captor!")
    time.sleep(1)
    print(" Some say this evil man's name is GAMEMAKER, but we really don't know.")
    time.sleep(1)
    print(" What do you think it is?")
    captor = raw_input()
    time.sleep(1)
    print(" So you think it is " + captor + "?")
    time.sleep(1)
    print("     Very well, find " + captor + " ASAP!")
    PLAY()
    return

def PLAY():
    print hp
    print lvl
    print atk
    print defn
    greenSlime(hp, lvl, atk, defn)
    return

def greenSlime(php, plvl, patk, pdefn):
    MHP = 10
    MLVL = 1
    MATK = 2
    MDEF = 2
    print "Green Slime - "
    print " HP: 10"
    print " LVL: 1"
    print " ATK: 2"
    print " DEF: 2"
    print "ATK OR DEF?"

LON()

I would like to use hp, lvl, atk, and defn variables that were declared in the LON function, in the PLAY function. I’m sure there is a simpler way then passing parameters.

Answer 1

Just declaring a variable inside global will not work. The global keyword is to ask the interpreter not to treat something as a local (overriding a global variable with the same name) when assigning a value to it. What you need to do is define the variable at a scope above the functions which are supposed to share it. Note that you don’t need to declare a variable global in function for read-only access. When the interpreter does not find the variable in local scope it automatically looks for it at outer scope. But in case of assignment statement, it creates a new local variable.

So what you want to do is :

hp = None
lvl = None
atk = None
defn = None

def LON():
    global hp, lvl, atk, defn
    # rest of LON

# rest of the functions

But I should warn you that globals are bad programming practice and passing parameters is the right way to do it.