counter:
计数器（Counter）是一个容器，用来跟踪值出现了多少次。
排序加去重
代码示例:
from collections import Counter
mylist=['tom','adel','alex','adel','tom','tom','adel','tom','alex']
myset = Counter(mylist)
print myset
运行结果:
[('tom', 4), ('adel', 3), ('alex', 2)]
set:
set()函数返回列表中不同的字符串组成的集合
去重!
代码示例:
mylist=['tom','adel','alex','adel','tom','tom','adel','tom','alex']
myset =set(mylist)
for item in myset:
print "name:%s num:%d" %(item,mylist.count(item))
运行结果:
name:adel num:3
name:alex num:2
name:tom num:4
