【python】listのソート方法を世界一わかりやすく解説

numbers = [4, 2, 9, 1]
numbers.sort()
print(numbers)  # 出力: [1, 2, 4, 9]

numbers = [4, 2, 9, 1]
sorted_numbers = sorted(numbers)
print(sorted_numbers)  # 出力: [1, 2, 4, 9]
print(numbers)  # 出力: [4, 2, 9, 1] （元のリストは変更されません）

words = ["apple", "banana", "cherry", "date"]
words.sort(key=lambda x: len(x))
print(words)  # 出力: ['date', 'apple', 'banana', 'cherry']

words = ["apple", "banana", "cherry", "kaki"]
words.sort(key=lambda x: x[::-1])  # ::-1はxの要素を逆順にする
print(words)

# 出力: ['banana', 'apple', 'kaki', 'cherry']

"apple"[::-1]  # 出力: 'elppa'
"banana"[::-1]  # 出力: 'ananab'
"cherry"[::-1]  # 出力: 'yrrehc'
"kaki"[::-1]  # 出力: 'ikak'

numbers = [-10, 20, -30, 15]
numbers.sort(key=lambda x: abs(x))
print(numbers)

# 出力: [-10, 15, 20, -30]

numbers.sort(key=lambda x: abs(x), reverse=True)
print(numbers)

# 出力: [-30, 20, 15, -10]

words = ["abc", "abcd", "bcd", "bcde", "bbbbbb", "aaaaaa"]
words.sort(key=lambda x: (x[0], len(x)))
print(words)

# 出力: ['abc', 'abcd', 'aaaaaa', 'bcd', 'bcde', 'bbbbbb']

people = [{"name": "Alice", "age": 30}, {"name": "Bob", "age": 25}, {"name": "Charlie", "age": 35}]
people.sort(key=lambda x: x["age"])
print(people)

# 出力: [{'name': 'Bob', 'age': 25}, {'name': 'Alice', 'age': 30}, {'name': 'Charlie', 'age': 35}]

products = [("Laptop", 900), ("Smartphone", 600), ("Tablet", 300)]
products.sort(key=lambda x: x[1])
print(products)

# 出力: [('Tablet', 300), ('Smartphone', 600), ('Laptop', 900)]