Python 进程之间共享数据(全局变量)

进程之间共享数据(数值型)：

import multiprocessing

def  func(num):
    num.value=10.78  #子进程改变数值的值，主进程跟着改变

if  __name__=="__main__":
    num=multiprocessing.Value("d",10.0) # d表示数值,主进程与子进程共享这个value。（主进程与子进程都是用的同一个value）
    print(num.value)

    p=multiprocessing.Process(target=func,args=(num,))
    p.start()
    p.join()

    print(num.value)

进程之间共享数据(数组型)：

import multiprocessing
import ctypes

def  func(num):
    num[2]=9999   #子进程改变数组，主进程跟着改变

if  __name__=="__main__":
    num=multiprocessing.Array(ctypes.c_int,[1,2,3,4,5])   #主进程与子进程共享这个数组
    print(num[:])

    p=multiprocessing.Process(target=func,args=(num,))
    p.start() 
    p.join()

    print(num[:])

ctypes支持的原生数据类型如下:

ctypes类型	C 类型	Python 类型
c_char	char	1-character string
c_wchar	wchar_t	1-character unicode string
c_byte	char	int/long
c_ubyte	unsigned char	int/long
c_bool	bool	bool
c_short	short	int/long
c_ushort	unsigned short	int/long
c_int	int	int/long
c_uint	unsigned int	int/long
c_long	long	int/long
c_ulong	unsigned long	int/long
c_longlong	__int64 or longlong	int/long
c_ulonglong	unsigned __int64 or unsigned long long	int/long
c_float	float	float
c_double	double	float
c_longdouble	long double float	float
c_char_p	char *	string or None
c_wchar_p	wchar_t *	unicode or None
c_void_p	void *	int/long or None

进程之间共享数据(dict,list)：

import multiprocessing

def func(mydict,mylist):
    mydict["index1"]="aaaaaa"   #子进程改变dict,主进程跟着改变
    mydict["index2"]="bbbbbb"
    mylist.append(11)        #子进程改变List,主进程跟着改变
    mylist.append(22)
    mylist.append(33)

if __name__=="__main__":
    with multiprocessing.Manager() as MG:   #重命名
        mydict=multiprocessing.Manager().dict()   #主进程与子进程共享这个字典
        mylist=multiprocessing.Manager().list(range(5))   #主进程与子进程共享这个List

        p=multiprocessing.Process(target=func,args=(mydict,mylist))
        p.start()
        p.join()

        print(mylist)
        print(mydict)