先来看看运行效果图：
利用多个线程处理搜索的问题，我们可以发现他很快....
下面是代码部分：
# a parallelized find(1) using the thread module.# this demonstrates the use of a work queue and worker threads.# it really does do more stats/sec when using multiple threads,# although the improvement is only about 20-30 percent.# (that was 8 years ago. in 2002, on linux, i can't measure# a speedup. :-( )# i'm too lazy to write a command line parser for the full find(1)# command line syntax, so the predicate it searches for is wired-in,# see function selector() below. (it currently searches for files with# world write permission.)# usage: parfind.py [-w nworkers] [directory] ...# default nworkers is 4import sysimport getoptimport timeimport osfrom stat import *import _thread as thread# work queue class. usage:# wq = workq()# wq.addwork(func, (arg1, arg2, ...)) # one or more calls# wq.run(nworkers)# the work is done when wq.run() completes.# the function calls executed by the workers may add more work.# don't use keyboard interrupts!class workq: # invariants: # - busy and work are only modified when mutex is locked # - len(work) is the number of jobs ready to be taken # - busy is the number of jobs being done # - todo is locked iff there is no work and somebody is busy def __init__(self): self.mutex = thread.allocate() self.todo = thread.allocate() self.todo.acquire() self.work = [] self.busy = 0 def addwork(self, func, args): job = (func, args) self.mutex.acquire() self.work.append(job) self.mutex.release() if len(self.work) == 1: self.todo.release() def _getwork(self): self.todo.acquire() self.mutex.acquire() if self.busy == 0 and len(self.work) == 0: self.mutex.release() self.todo.release() return none job = self.work[0] del self.work[0] self.busy = self.busy + 1 self.mutex.release() if len(self.work) > 0: self.todo.release() return job def _donework(self): self.mutex.acquire() self.busy = self.busy - 1 if self.busy == 0 and len(self.work) == 0: self.todo.release() self.mutex.release() def _worker(self): time.sleep(0.00001) # let other threads run while 1: job = self._getwork() if not job: break func, args = job func(*args) self._donework() def run(self, nworkers): if not self.work: return # nothing to do for i in range(nworkers-1): thread.start_new(self._worker, ()) self._worker() self.todo.acquire()# main programdef main(): nworkers = 4 #print(getopt.getopt(sys.argv[1:], '-w:')) opts, args = getopt.getopt(sys.argv[1:], '-w:') for opt, arg in opts: if opt == '-w': nworkers = int(arg) if not args: #print(os.curdir) args = [os.curdir] wq = workq() for dir in args: wq.addwork(find, (dir, selector, wq)) t1 = time.time() wq.run(nworkers) t2 = time.time() sys.stderr.write('total time %r sec.\n' % (t2-t1))# the predicate -- defines what files we look for.# feel free to change this to suit your purposedef selector(dir, name, fullname, stat): # look for world writable files that are not symlinks return (stat[st_mode] & 0o002) != 0 and not s_islnk(stat[st_mode])# the find procedure -- calls wq.addwork() for subdirectoriesdef find(dir, pred, wq): try: names = os.listdir(dir) except os.error as msg: print(repr(dir), ':', msg) return for name in names: if name not in (os.curdir, os.pardir): fullname = os.path.join(dir, name) try: stat = os.lstat(fullname) except os.error as msg: print(repr(fullname), ':', msg) continue if pred(dir, name, fullname, stat): print(fullname) if s_isdir(stat[st_mode]): if not os.path.ismount(fullname): wq.addwork(find, (fullname, pred, wq))# call the main programmain()
希望本文所述对大家python程序设计有所帮助。