两个独立的进程没有同时运行

Question

I wrote a program to analyse StackOverflow 2019 developer survey(.csv) file and used Matplotlib to present data.

Below is my code:

import multiprocessing
from matplotlib import pyplot as plt
import re
import analyze
import deleteCache


def makepie(countries, contributors):
    plt.style.use('fivethirtyeight')
    plt.title(
        'Top 5 Countries With Contribution IN Open Source Softwares(OSS)')
    plt.pie(contributors, labels=countries, shadow=True,
            startangle=90,
            autopct='%2.2f%%',
            wedgeprops={
                'edgecolor': 'black'})
    plt.tight_layout()
    plt.show()


def makebar(countries, contributors):
    index = range(1, 6)
    plt.style.use('fivethirtyeight')
    plt.title(
        'Top 5 Countries With Contribution IN Open Source Softwares(OSS)')
    plt.bar(index, contributors)
    plt.xlabel('Countries')
    plt.ylabel('Contributors')
    plt.xticks(ticks=index, labels=countries)
    plt.show()


def getdata():
    pattern = re.compile(r'([A-Za-z ]+),(\d+)')
    countries = []
    contributors = []
    with open(file='Top5ContributingCountries.csv', mode='r', encoding='utf-8') as f:
        for line in f:
            search = pattern.match(line)
            countries.append(search.group(1))
            contributors.append(int(search.group(2)))
    print('Enter Your Choice')
    print(f'1 For Pie Chart\n2 For Bar Chart\n3 For Both')
    option = input()
    if(option == '1'):
        makepie(countries, contributors)
    elif(option == '2'):
        makebar(countries, contributors)
    else:
        makepie(countries, contributors)
        makebar(countries, contributors)


if __name__ == "__main__":
    analyze.analyzedata()
    getdata()
    deleteCache.deleteCache()

I implemented multithreading in getdata():

def getdata():
    pattern = re.compile(r'([A-Za-z ]+),(\d+)')
    countries = []
    contributors = []
    with open(file='Top5ContributingCountries.csv', mode='r', encoding='utf-8') as f:
        for line in f:
            search = pattern.match(line)
            countries.append(search.group(1))
            contributors.append(int(search.group(2)))
    print('Enter Your Choice')
    print(f'1 For Pie Chart\n2 For Bar Chart\n3 For Both')
    option = input()
    p1=multiprocessing.Process(target=makepie(countries, contributors))
    p2=multiprocessing.Process(target=makebar(countries, contributors))
    if(option == '1'):
        p1.start()
    elif(option == '2'):
        p2.start()
    else:
        p1.start()
        p2.start()

But piechart and barchart are not opening simultaneously if option='3' . If option='1' or option='2' it should only run p1 or p2 respectively but both the processes are running one after another.

What is wrong in my code?

Answer 1

target is assigned the return value of calling makepie and makebar , which calls them instantly and is the equivalent to setting target=None in this case. target should be assigned the function and args should be assigned the arguments:

p1=multiprocessing.Process(target=makepie,args=(countries, contributors))
p2=multiprocessing.Process(target=makebar,args=(countries, contributors))