【Python】if文とfor文を1行で書く【リスト内包表記・3項演算子】

1nums = [1, 2, 3, 4, 5, 6]
2nums_mul_2 = [n*2 for n in nums]
3print(nums_mul_2)
4# [2, 4, 6, 8, 10, 12]

1# タプルをリスト内包表記でループさせる
2tuple_a = ("a", "b", "c")
3list_d = [f"t_{a}" for a in tuple_a]
4print(list_d)
5# ['t_a', 't_b', 't_c']
6
7# 辞書の値をリスト内包表記でループさせる
8dict_a = {"a": 1, "b": 2, "c": 3}
9list_e = [v*2  for v in dict_a.values()]
10print(list_e)
11# [2, 4, 6]
12
13# 辞書のキーをリスト内包表記でループさせる
14dict_a = {"a": 1, "b": 2, "c": 3}
15list_f = [f"f_{k}"  for k in dict_a.keys()]
16print(list_f)
17# ['f_a', 'f_b', 'f_c']
18
19# 辞書のキーと値をループさせる
20dict_a = {"a": 1, "b": 2, "c": 3}
21list_g = [f"{k}_{v}"  for k, v in dict_a.items()]
22print(list_g)
23# ['a_1', 'b_2', 'c_3']

1list_a = ["a", "b", "c"]
2list_b = ["A", "B", "C"]
3# 辞書を辞書内包表記で作成
4dict_b = {a: b for a, b in zip(list_a, list_b)}
5print(dict_b)
6# {'a': 'A', 'b': 'B', 'c': 'C'}

1list_a = ["a", "b", "c"]
2gen_a = (f"g_{a}" for a in list_a)
3print(gen_a)
4# <generator object <genexpr> at 0x105a0cac0>

1a = 2
2num_type = "odds" if a % 2 == 1 else "even"
3print(num_type)
4# even
5
6a = 3
7num_type = "odds" if a % 2 == 1 else "even"
8print(num_type)
9# odds

1nums = [1, 2, 3, 4, 5, 6]
2
3odds = [num for num in nums if num % 2 == 1]
4evens = [num for num in nums if num %2 == 0]
5print(odds)
6print(evens)
7# [1, 3, 5]
8# [2, 4, 6]

1nums = [1, 2, 3, 4, 5, 6]
2
3num_types = ["odd" if num %2 == 1 else "even" for num in nums]
4print(num_types)
5# ['odd', 'even', 'odd', 'even', 'odd', 'even']

1# リスト内包表記
2nums = [1, 2, 3, 4, 5, 6]
3nums_mul_2 = [n*2 for n in nums]
4print(nums_mul_2)
5# [2, 4, 6, 8, 10, 12]
6
7# 辞書内包表記
8list_a = ["a", "b", "c"]
9dict_a = {v: i*2 for i, v in enumerate(list_a)}
10print(dict_a)
11# {'a': 0, 'b': 2, 'c': 4}
12
13# ３項演算子
14a = 2
15num_type = "odds" if a % 2 == 1 else "even"
16print(num_type)
17# even
18
19# if文とリスト内包表記
20nums = [1, 2, 3, 4, 5, 6]
21odds = [num for num in nums if num % 2 == 1]
22print(odds)
23# [1, 3, 5]
24
25# if-else文とリスト内包表記
26nums = [1, 2, 3, 4, 5, 6]
27num_types = ["odd" if num %2 == 1 else "even" for num in nums]
28print(num_types)
29# ['odd', 'even', 'odd', 'even', 'odd', 'even']