[Python] - Sort / Reverse

1. Sort

---

• Only List(In-place)
• Reverse = [::-1]

a = [1,5,2,4]
a.sort()
> [1,2,4,5]

# a.sort() -> a[::-1]
a.sort(reverse=True)
> [5,4,2,1]

 

2. Sorted

---

• Use Iterable Object
• A simple ascending sort and returns a new sorted list
• key parameter call function for list element 

#iterable dict
temp = {1: 'D', 2: 'B', 3: 'B', 4: 'E', 5: 'A'}

sorted(temp)
> [1, 2, 3, 4, 5]

sorted(temp.items())
> [(1, 'D'), (2, 'B'), (3, 'B'), (4, 'E'), (5, 'A')]

sorted(temp.items() , key = lambda x:x[1] )
> [(5, 'A'), (2, 'B'), (3, 'B'), (1, 'D'), (4, 'E')]

# class example
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))

student_objects = [
     Student('john', 'A', 15),
     Student('jane', 'B', 12),
     Student('dave', 'B', 10),
]

sorted(student_objects, key=lambda student: student.age)