写入全局数组的显式元素显然不需要全局声明，尽管“批发”写入它确实有这样的要求：

import numpy as np

hostValue = 3.14159
hostArray = np.array([2., 3.])
hostMatrix = np.array([[1.0, 0.0],[ 0.0, 1.0]])

def func1():
    global hostValue    # mandatory, else local.
    hostValue = 2.0

def func2():
    global hostValue    # mandatory, else UnboundLocalError.
    hostValue += 1.0

def func3():
    global hostArray    # mandatory, else local.
    hostArray = np.array([14., 15.])

def func4():            # no need for globals
    hostArray[0] = 123.4

def func5():            # no need for globals
    hostArray[1] += 1.0

def func6():            # no need for globals
    hostMatrix[1][1] = 12.

def func7():            # no need for globals
    hostMatrix[0][0] += 0.33

func1()
print "After func1(), hostValue = ", hostValue
func2()
print "After func2(), hostValue = ", hostValue
func3()
print "After func3(), hostArray = ", hostArray
func4()
print "After func4(), hostArray = ", hostArray
func5()
print "After func5(), hostArray = ", hostArray
func6()
print "After func6(), hostMatrix = \n", hostMatrix
func7()
print "After func7(), hostMatrix = \n", hostMatrix

您可以在其他函数中使用全局变量，方法是在为其赋值的每个函数中将其声明为全局变量：

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

由于不清楚globvar=1是创建本地变量还是更改全局变量，Python默认创建本地变量，并使用全局关键字显式选择其他行为。

如果要在模块间共享全局变量，请参阅其他答案。

您的意思是使用以下方法：

globvar = 5

def f():
    var = globvar
    print(var)

f()  # Prints 5

但更好的方法是像这样使用全局变量：

globvar = 5
def f():
    global globvar
    print(globvar)
f()   #prints 5

两者的输出相同。

Initialized = 0  #Here This Initialized is global variable  

def Initialize():
     print("Initialized!")
     Initialized = 1  #This is local variable and assigning 1 to local variable
while Initialized == 0:  

这里我们比较全局变量Initialized为0，因此当循环条件为true时

     Initialize()

函数将被调用。循环将是无限的

#if we do Initialized=1 then loop will terminate  

else:
    print("Lets do something else now!")

试试看：

def x1():
    global x
    x += 1
    print('x1: ', x)

def x2():
    global x
    x = x+1
    print('x2: ', x)

x = 5
print('x:  ', x)
x1()
x2()

# Output:
# x:   5
# x1:  6
# x2:  7

类似此代码：

myVar = 12

def myFunc():
  myVar += 12

Key:

如果在字符串外部声明变量，它将变为全局变量。

如果在字符串中声明变量，它将变为本地变量。

如果要在字符串中声明全局变量，请在要声明的变量之前使用关键字global：

myVar = 124
def myFunc():
  global myVar2
  myVar2 = 100
myFunc()
print(myVar2)

然后文档中有100个。