Python 3.x 中如何使用itertools模块进行迭代器操作

from itertools import count

for i in count(5, 2):
    if i > 10:
        break
    print(i)

5
7
9
11

from itertools import cycle

colors = ['red', 'green', 'blue']
count = 0

for color in cycle(colors):
    if count > 10:
        break
    print(color)
    count += 1

red
green
blue
red
green
blue
red
green
blue
red
green

from itertools import repeat

for i in repeat('hello', 3):
    print(i)

hello
hello
hello

from itertools import chain

colors = ['red', 'green', 'blue']
numbers = [1, 2, 3]

for item in chain(colors, numbers):
    print(item)

red
green
blue
1
2
3

from itertools import compress

letters = ['a', 'b', 'c', 'd', 'e']
mask = [True, False, False, True, False]

filtered_letters = compress(letters, mask)

for letter in filtered_letters:
    print(letter)

a
d

from itertools import dropwhile

numbers = [1, 3, 5, 2, 4, 6]

result = dropwhile(lambda x: x < 4, numbers)

for number in result:
    print(number)

5
2
4
6

from itertools import takewhile

numbers = [1, 3, 5, 2, 4, 6]

result = takewhile(lambda x: x < 4, numbers)

for number in result:
    print(number)

1
3

from itertools import permutations

items = ['a', 'b', 'c']

result = permutations(items)

for permutation in result:
    print(permutation)

('a', 'b', 'c')
('a', 'c', 'b')
('b', 'a', 'c')
('b', 'c', 'a')
('c', 'a', 'b')
('c', 'b', 'a')