SyntaxWarning: name 'x' is assigned to before global declaration global color Python

SyntaxWarning: name 'x' is assigned to before global declaration global color Python

这种报错很大原因是在同一个函数重复使用了global 声明
举个例子x = 0

def func(a, b, c):
if a == b:
global x
x = 10
elif b == c:
global x
x = 20在每次使用变量之前，不要立即进行全局声明，只需要在函数开始处使用它一次就行了，下面是正确的写法x = 0

def func(a, b, c):
global x # <- here
if a == b:
x = 10
elif b == c:
x = 20参考连接：http://effbot.org/zone/syntaxwarning-name-assigned-to-before-global-declaration.htm