从for循环运行多个程序

Question

该程序一一打印出每个文本文件的行数：

files = glob.glob('*.txt') # 5 files
for f in files:
  with open(f,'r') as fi:
     lines = fi.read().splitlines()
     print len(lines)

如何编写代码，使其同时运行5个程序并分别在每个程序中打印行数？

Answer 1

这是您的程序的多线程版本：

import threading

# called by each thread
def do_task(f) :
  with open(f,'r') as fi:
     lines = fi.read().splitlines()
     print len(lines)

threads = []
files = glob.glob('*.txt') # 5 files
for f in files:
    t = threading.Thread(target=do_task, args = (f))
    threads.append(t)
    t.start()

for t in threads :
    t.join()

有趣的是，这里有多进程版本：

from multiprocessing import Process

# called by each thread
def do_task(f, l) :
  with open(f,'r') as fi:
     lines = fi.read().splitlines()
     l.append(lines)

lengths = []
processes = []
files = glob.glob('*.txt') # 5 files
for f in files:
    p = Process(target=do_task, args = (f,lengths,))
    processes.append(p)
    p.start()

for p in processes :
    p.join()

for l in lengths:
    print l