python多線程場景下print丟失

python多線程情況下，print輸出會出現丟失的情況，而logging模塊的日志輸出不會。

以下是示例代碼，多運行幾次就會發現這個有意思的現象

# coding:utf-8
import threading
import time
import logging

def action(arg):
    time.sleep(1)
    logging.info('sub thread start!the thread name is:%s\r' % threading.currentThread().getName())
    logging.info('the arg is:%s\r' %arg)
    print('sub thread start!the thread name is:%s\r' % threading.currentThread().getName())
    print('the arg is:%s\r' %arg)
    time.sleep(1)

if __name__=="__main__":
    logging.basicConfig(level=logging.INFO)
    for i in range(4):
        t =threading.Thread(target=action,args=(i,))
        t.setDaemon(False)#設置線程為后台線程
        t.start()

print('main_thread end!')