Python 中的排序

来源：互联网发布：finale mac 编辑：程序博客网时间：2024/05/16 00:46

早在学习perl的时候就总结过排序问题 Schwartzian Transform(施瓦茨变换)

现在，我们来看看在python中如何实现：
Schwartzian transform的中心思想就是Decorate-Sort-Undecorate

class Student:    def __init__(self, name, grade, age):        self.name = name        self.grade = grade        self.age = age    def __repr__(self):        return repr((self.name, self.grade, self.age))s1 = Student('Ace', 'S', 12)s2 = Student('David', 'A', 10)s3 = Student('Jie', 'S', 13)s4 = Student('Shawn', 'A', 11)students = [ s1, s2, s3, s4 ]decorated = [(s.grade, s.age, s) for s in students]decorated.sort()#undecoratesorted_students = [ s for _,_,s in decorated ]print sorted_students# [('David', 'A', 10), ('Shawn', 'A', 11), ('Jie', 'S', 12), ('Ace', 'S', 13)]

当然，既然用了python，就应该pythonic到底，试试下面的方法吧：

print sorted(students, key=lambda s: s.grade and s.age)

from operator import attrgetterprint sorted(students, key=attrgetter('grade', 'age'))

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