global variable in python

在Python 中修改到全域變數時要宣告global

globvar = 0
def set_globvar_to_one():
    global globvar    # Needed to modify global copy of globvar
    globvar = 1
def print_globvar():
    print globvar     # No need for global declaration to read value of globvar

set_globvar_to_one()
print_globvar()       # Prints 1