list sort by key python

1# sort() will change the original list into a sorted list
2vowels = ['e', 'a', 'u', 'o', 'i']
3vowels.sort()
4# Output:
5# ['a', 'e', 'i', 'o', 'u']
6
7# sorted() will sort the list and return it while keeping the original
8sortedVowels = sorted(vowels)
9# Output:
10# ['a', 'e', 'i', 'o', 'u']

1>>> sorted(student_tuples, key=itemgetter(2))
2[('dave', 'B', 10), ('jane', 'B', 12), ('john', 'A', 15)]
3

1>>> student_tuples = [
2...     ('john', 'A', 15),
3...     ('jane', 'B', 12),
4...     ('dave', 'B', 10),
5... ]
6>>> sorted(student_tuples, key=lambda student: student[2])   
7# sort by age
8[('dave', 'B', 10), ('jane', 'B', 12), ('john', 'A', 15)]
9

1>>> x = [1 ,11, 2, 3]
2>>> y = sorted(x)
3>>> x
4[1, 11, 2, 3]
5>>> y
6[1, 2, 3, 11]
7

1>>> class Student:
2...     def __init__(self, name, grade, age):
3...         self.name = name
4...         self.grade = grade
5...         self.age = age
6...     def __repr__(self):
7...         return repr((self.name, self.grade, self.age))
8

1old_list = [3,2,1]
2old_list.sort()