python笔记3 小小的复习下排序

排序:

3,sorted()

 a= [1,2,3,4]

 sorted(a,reverse=True)

4,sort()

 a.sort(key=int,reverse=True)

5,多级排序

  引入模块operator

 imporrt  operator

 >>> a=[(1,2,3),(3,4,5),(0,1,2)]

>>> import operator

>>> a.sort(key=operator.itemgetter(1,2))

>>> a

[(0, 1, 2), (1, 2, 3), (3, 4, 5)]

6,占位符的展示

>>> "i is %s in %s" % ('tom','shanghai')

'i is tom in shanghai'

>>> "%(who)s is a %(gender)s" % {'who':'i','gender':'boy'}

'i is a boy'

>>> "{who} is a {gender}".format(who='i',gender='boy')

'i is a boy'