파이썬 정렬

기본

print(sorted([5, 2, 3, 1, 4]))
# [1, 2, 3, 4, 5]

print(sorted([5, 2, 3, 1, 4], reverse=True))
# [5, 4, 3, 2, 1]

a = [5, 2, 3, 1, 4]
a.sort()
print(a)
# [1, 2, 3, 4, 5]

print(sorted({1: 'D', 2: 'B', 3: 'B', 4: 'E', 5: 'A'}))
# [1, 2, 3, 4, 5]

키

student_tuples = [
    ('john', 'A', 15),
    ('jane', 'B', 12),
    ('dave', 'B', 10),
]
print(sorted(student_tuples, key=lambda student: student[2]))  # sort by age
# [('dave', 'B', 10), ('jane', 'B', 12), ('john', 'A', 15)]

operator.itemgetter를 사용하는 것이 더 빠르다. 

from operator import itemgetter

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

print(sorted(student_tuples, key=itemgetter(2)))  # sort by age

다중 정렬

from operator import itemgetter

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

print(sorted(student_tuples, key=itemgetter(1, 2)))  # sort by grade, age
# [('john', 'A', 15), ('dave', 'B', 10), ('jane', 'B', 12)]

복잡한 정렬

크다면 1, 같다면 0, 작다면 -1을 리턴

from functools import cmp_to_key


def compare(a, b):
    return int(b + a) - int(a + b)


nums = ['6', '10', '2']
print(sorted(nums, key=cmp_to_key(compare)))

# ['6', '2', '10']

https://wikidocs.net/109303

029 순서대로 좌표를 정렬하려면? ― functools.cmp_to_key