实例：由字符串创建一个作业评分列表，做增删改查询统计遍历操作。
例如，查询第一个3分的下标
统计1分的同学有多少个，3分的同学有多少个
>>> a=list(‘1123231132213‘) >>> a [‘1‘, ‘1‘, ‘2‘, ‘3‘, ‘2‘, ‘3‘, ‘1‘, ‘1‘, ‘3‘, ‘2‘, ‘2‘, ‘1‘, ‘3‘] >>> a[3]=‘4‘ >>> a [‘1‘, ‘1‘, ‘2‘, ‘4‘, ‘2‘, ‘3‘, ‘1‘, ‘1‘, ‘3‘, ‘2‘, ‘2‘, ‘1‘, ‘3‘] >>> a.index(‘3‘) 5 >>> a.append(‘5‘) >>> a [‘1‘, ‘1‘, ‘2‘, ‘4‘, ‘2‘, ‘3‘, ‘1‘, ‘1‘, ‘3‘, ‘2‘, ‘2‘, ‘1‘, ‘3‘, ‘5‘] >>> a.pop(-3) ‘1‘ >>> a [‘1‘, ‘1‘, ‘2‘, ‘4‘, ‘2‘, ‘3‘, ‘1‘, ‘1‘, ‘3‘, ‘2‘, ‘2‘, ‘3‘, ‘5‘] >>> len(a) 13 >>> a.insert(1,‘hello‘) >>> a [‘1‘, ‘hello‘, ‘1‘, ‘2‘, ‘4‘, ‘2‘, ‘3‘, ‘1‘, ‘1‘, ‘3‘, ‘2‘, ‘2‘, ‘3‘, ‘5‘]
>>> d={‘09‘:‘66‘,‘05‘:‘80‘,‘14‘:‘78‘,‘23‘:‘90‘}
>>> d[‘14‘]
‘78‘
>>> d.keys()
dict_keys([‘09‘, ‘05‘, ‘14‘, ‘23‘])
>>> d.values()
dict_values([‘66‘, ‘80‘, ‘78‘, ‘90‘])
>>> d.items()
dict_items([(‘09‘, ‘66‘), (‘05‘, ‘80‘), (‘14‘, ‘78‘), (‘23‘, ‘90‘)])
>>> d.get(‘05‘,‘66‘)
‘80‘
>>> d.pop(‘23‘,‘80‘)
‘90‘
>>> d
{‘09‘: ‘66‘, ‘05‘: ‘80‘, ‘14‘: ‘78‘}
>>> ‘04‘ in d
False
>>> ‘05‘in d
True
>>> del(d[‘09‘])
>>> d
{‘05‘: ‘80‘, ‘14‘: ‘78‘}
>>> d["02"]="90"
>>> d
{‘05‘: ‘80‘, ‘14‘: ‘78‘, ‘02‘: ‘90‘}
原文：http://www.cnblogs.com/millmill/p/7559762.html