[python] comprehension

>>>ls = []
>>>for num in range(1, 11):
        if num % 2 == 1:
            ls.append(num)
>>>ls
[1, 3, 5, 7, 9]

# comprehension을 사용한 방법
>>>ls = [num for num in range(1, 11) if >>>num % 2 == 1]
>>>ls
[1, 3, 5, 7, 9]

>>>rows = range(1, 5)
>>>cols = range(1, 3)
>>>for row in rows:
        for col in cols:
            print(row, col)
1 1
1 2
2 1
2 2
3 1
3 2
4 1
4 2

# comprehension을 사용한 방법

# (row, col) 튜플 리스트를 만들어서 cells 변수에 할당
>>>rows = range(1, 5)
>>>cols = range(1, 3)
>>>cells = [(row, col) for row in rows for col in cols]
# 각 튜플로부터 row와 col만 출력하도록 tuple unpacking
>>>for row, col in cells:
        print(row, col)
1 1
1 2
2 1
2 2
3 1
3 2
4 1
4 2

>>>word = 'datascience'
>>>letter_count = {x: word.count(x) for x in word}
>>>letter_count
{'d': 1, 'a': 2, 't': 1, 's': 1, 'c': 2, 'i': 1, 'e': 2, 'n': 1}

a_set = {num in num in range(1, 6) if num % 3 == 1}
a_set
{1, 4}

nums = (num for num in range(1, 6))

for num in nums:
        print(num)
1
2
3
4
5

nums = (num for num in range(1, 6))
>>> num_list = list(nums)
>>> num_list