标签：
在读取一组数据创字典时，可以使用setdefaul函数对字典进行初始化，这样很方便呀，不用每次都检查是否为新值
比如实际任务中，我希望把以人名为key的字典改换成以movie为key的字典就可以这样写
1 namekey_dic = {‘Lisa Rose‘: {‘Lady in the Water‘: 2.5, ‘Snakes on a Plane‘: 3.5, 2 ‘Just My Luck‘: 3.0, ‘Superman Returns‘: 3.5, ‘You, Me and Dupree‘: 2.5, 3 ‘The Night Listener‘: 3.0}, 4 ‘Gene Seymour‘: {‘Lady in the Water‘: 3.0, ‘Snakes on a Plane‘: 3.5, 5 ‘Just My Luck‘: 1.5, ‘Superman Returns‘: 5.0, ‘The Night Listener‘: 3.0, 6 ‘You, Me and Dupree‘: 3.5}, 7 ‘Michael Phillips‘: {‘Lady in the Water‘: 2.5, ‘Snakes on a Plane‘: 3.0, 8 ‘Superman Returns‘: 3.5, ‘The Night Listener‘: 4.0}, 9 ‘Claudia Puig‘: {‘Snakes on a Plane‘: 3.5, ‘Just My Luck‘: 3.0, 10 ‘The Night Listener‘: 4.5, ‘Superman Returns‘: 4.0, 11 ‘You, Me and Dupree‘: 2.5}, 12 ‘Mick LaSalle‘: {‘Lady in the Water‘: 3.0, ‘Snakes on a Plane‘: 4.0, 13 ‘Just My Luck‘: 2.0, ‘Superman Returns‘: 3.0, ‘The Night Listener‘: 3.0, 14 ‘You, Me and Dupree‘: 2.0}, 15 ‘Jack Matthews‘: {‘Lady in the Water‘: 3.0, ‘Snakes on a Plane‘: 4.0, 16 ‘The Night Listener‘: 3.0, ‘Superman Returns‘: 5.0, ‘You, Me and Dupree‘: 3.5}, 17 ‘Toby‘: {‘Snakes on a Plane‘: 4.5, ‘You, Me and Dupree‘: 1.0, ‘Superman Returns‘: 4.0} 18 } 19 20 def transform(scorelist): 21 movielist = {} 22 for person in scorelist: 23 for movie in scorelist[person]: 24 movielist.setdefault(movie, {}) 25 movielist[movie][person] = scorelist[person][movie] 26 return movielist 27 28 moviekey_dic = transform(namekey_dic)
print moviekey_dic的结果为：
1 {‘Lady in the Water‘: {‘Lisa Rose‘: 2.5, ‘Jack Matthews‘: 3.0, ‘Michael Phillips‘: 2.5, ‘Gene Seymour‘: 3.0, ‘Mick LaSalle‘: 3.0}, ‘Snakes on a Plane‘: {‘Jack Matthews‘: 4.0, ‘Mick LaSalle‘: 4.0, ‘Claudia Puig‘: 3.5, ‘Lisa Rose‘: 3.5, ‘Toby‘: 4.5, ‘Gene Seymour‘: 3.5, ‘Michael Phillips‘: 3.0}, ‘Just My Luck‘: {‘Claudia Puig‘: 3.0, ‘Lisa Rose‘: 3.0, ‘Gene Seymour‘: 1.5, ‘Mick LaSalle‘: 2.0}, ‘Superman Returns‘: {‘Jack Matthews‘: 5.0, ‘Mick LaSalle‘: 3.0, ‘Claudia Puig‘: 4.0, ‘Lisa Rose‘: 3.5, ‘Toby‘: 4.0, ‘Gene Seymour‘: 5.0, ‘Michael Phillips‘: 3.5}, ‘The Night Listener‘: {‘Jack Matthews‘: 3.0, ‘Mick LaSalle‘: 3.0, ‘Claudia Puig‘: 4.5, ‘Lisa Rose‘: 3.0, ‘Gene Seymour‘: 3.0, ‘Michael Phillips‘: 4.0}, ‘You, Me and Dupree‘: {‘Jack Matthews‘: 3.5, ‘Mick LaSalle‘: 2.0, ‘Claudia Puig‘: 2.5, ‘Lisa Rose‘: 2.5, ‘Toby‘: 1.0, ‘Gene Seymour‘: 3.5}}
标签：
原文地址：http://www.cnblogs.com/ivywenyuan/p/4744460.html
