本节书摘来自异步社区《Python极客项目编程 》一书中的第1章，第1.4节，作者 [美] Mahesh Venkitachalam，王海鹏 译，更多章节内容可以访问云栖社区“异步社区”公众号查看。
下面是完整的程序。在https://github.com/electronut/pp/tree/master/playlist/ ，你也可以找到本项目的代码和一些测试数据。
import re, argparse import sys from matplotlib import pyplot import plistlib import numpy as np def findCommonTracks(fileNames): """ Find common tracks in given playlist files, and save them to common.txt. """ # a list of sets of track names trackNameSets = [] for fileName in fileNames: # create a new set trackNames = set() # read in playlist plist = plistlib.readPlist(fileName) # get the tracks tracks = plist['Tracks'] # iterate through the tracks for trackId, track in tracks.items(): try: # add the track name to a set trackNames.add(track['Name']) except: # ignore pass # add to list trackNameSets.append(trackNames) # get the set of common tracks commonTracks = set.intersection(*trackNameSets) # write to file if len(commonTracks) > 0: f = open("common.txt", 'w') for val in commonTracks: s = "%s\n" % val f.write(s.encode("UTF-8")) f.close() print("%d common tracks found. " "Track names written to common.txt." % len(commonTracks)) else: print("No common tracks!") def plotStats(fileName): """ Plot some statistics by reading track information from playlist. """ # read in a playlist plist = plistlib.readPlist(fileName) # get the tracks from the playlist tracks = plist['Tracks'] # create lists of song ratings and track durations ratings = [] durations = [] # iterate through the tracks for trackId, track in tracks.items(): try: ratings.append(track['Album Rating']) durations.append(track['Total Time']) except: # ignore pass # ensure that valid data was collected if ratings == [] or durations == []: print("No valid Album Rating/Total Time data in %s." % fileName) return # scatter plot x= np.array(durations, np.int32) # convert to minutes x = x/60000.0 y = np.array(ratings, np.int32) pyplot.subplot(2, 1, 1) pyplot.plot(x, y, 'o') pyplot.axis([0, 1.05*np.max(x), -1, 110]) pyplot.xlabel('Track duration') pyplot.ylabel('Track rating') # plot histogram pyplot.subplot(2, 1, 2) pyplot.hist(x, bins=20) pyplot.xlabel('Track duration') pyplot.ylabel('Count') # show plot pyplot.show() def findDuplicates(fileName): """ Find duplicate tracks in given playlist. """ print('Finding duplicate tracks in %s...' % fileName) # read in playlist plist = plistlib.readPlist(fileName) # get the tracks from the Tracks dictionary tracks = plist['Tracks'] # create a track name dictionary trackNames = {} # iterate through tracks for trackId, track in tracks.items(): try: name = track['Name'] duration = track['Total Time'] # look for existing entries if name in trackNames: # if a name and duration match, increment the count # round the track length to the nearest second if duration//1000 == trackNames[name][0]//1000: count = trackNames[name][1] trackNames[name] = (duration, count+1) else: # add dictionary entry as tuple (duration, count) trackNames[name] = (duration, 1) except: # ignore pass # store duplicates as (name, count) tuples dups = [] for k, v in trackNames.items(): if v[1] > 1: dups.append((v[1], k)) # save duplicates to a file if len(dups) > 0: print("Found %d duplicates. Track names saved to dup.txt" % len(dups)) else: print("No duplicate tracks found!") f = open("dups.txt", 'w') for val in dups: f.write("[%d] %s\n" % (val[0], val[1])) f.close() # gather our code in a main() function def main(): # create parser descStr = """ This program analyzes playlist files (.xml) exported from iTunes. """ parser = argparse.ArgumentParser(description=descStr) # add a mutually exclusive group of arguments group = parser.add_mutually_exclusive_group() # add expected arguments group.add_argument('--common', nargs='*', dest='plFiles', required=False) group.add_argument('--stats', dest='plFile', required=False) group.add_argument('--dup', dest='plFileD', required=False) # parse args args = parser.parse_args() if args.plFiles: # find common tracks findCommonTracks(args.plFiles) elif args.plFile: # plot stats plotStats(args.plFile) elif args.plFileD: # find duplicate tracks findDuplicates(args.plFileD) else: print("These are not the tracks you are looking for.") # main method if __name__ == '__main__': main() 相关资源：Python极客项目编程