线程与队列，并在Python中同时打印

Question

我想完成关于线程模块的练习。在我的例子中，我只想创建只打印文件名的工作人员。

import optparse 
import os 
import queue 
import threading 

def main(): 
    opts, args = parse_options() 
    filelist = get_files(args) 
    worker_queue= queue.Queue() 

for i in range(opts.count): 
    threadnum  = "{0}: ".format(i+1) if opts.debug else "" 
    worker   = Worker(worker_queue, threadnum) 
    worker.daemon = True 
    worker.start() 
for file in filelist: 
    worker_queue.put(file) 
worker_queue.join() 

class Worker(threading.Thread): 


    def __init__(self, worker_queue, threadnum): 
     super().__init__() 
     self.worker_queue = worker_queue 
     self.threadnum  = threadnum 
     self.result   = [] 

    def run(self): 
     while True: 
      try: 
       file = self.worker_queue.get() 
       self.process(file) 
      finally: 
       self.worker_queue.task_done() 

    def process(self, file): 
     print("{0}{1}".format(self.threadnum, file)) 

def parse_options(): 

    parser  = optparse.OptionParser(
    usage  = "xmlsummary.py [options] [path] outputs a summary of the XML files in path; path defaults to .") 
    parser.add_option("-t", "--threads", dest = "count", default = 7,type = "int", help = ("the number of threads to use (1..20) [default %default]")) 
    parser.add_option("-v", "--verbose", default = False, action = "store_true", help = ("show verbose information if requested, [default %default]")) 
    parser.add_option("-d", "--debug", dest = "debug", default = False, action = "store_true", help = ("show debug information such as thread id, [default, %default]")) 
    opts, args = parser.parse_args() 

    if not (1 <= opts.count <= 20): 
     parser.error("threads must be in following range (1..20)") 

return opts, args 

def get_files(args): 
    filelist = [] 
    for item in args: 
    if os.path.isfile(item): 
     filelist.append(item) 
    else: 
     for root, dirs , files in os.walk(item): 
      for file in files: 
       filelist.append(os.path.join(root, file)) 
    return filelist 
main() 

此代码返回我-d选项（其中将包括在输出线程ID）：

1: C:\P\1.jpg2: C:\P\2.jpg3: C:\P\3chapter.bat4: C:\P\423.txt5: C:\P\a.txt6: C:\P\bike.dat7: C:\P\binary1.dat 

的第一个问题是： 所有线程在同一行打印出来，因为每个线程使用一个sys.stdout？

我有以下改变打印命令：

def process(self, file): 
print("{0}{1}\n".format(self.threadnum, file)) 

现在这个我有以下结果：

1: C:\P\1.jpg 
2: C:\P\2.jpg 
3: C:\P\3chapter.bat 
4: C:\P\423.txt 
5: C:\P\a.txt 
6: C:\P\bike.dat 
7: C:\P\binary1.dat 







1: C:\P\dckm.txt 
2: C:\P\dlkcm.txt 
3: C:\P\email.html 

第二个问题是： 如何从输出中删除空行？

Answer 1

你在正确的轨道上，sys.stdout。一个简单的solutin这两个问题会是这样

def tprint(msg): 
    sys.stdout.write(str(msg) + '\n') 
    sys.stdout.flush() 

的函数，用它来代替sys.stdout