import itertools

# 创建一个无限的迭代器, 起始值为0, 步长为1
count_iter = itertools.count(start=0, step=1)
for n in count_iter:
    if n > 10:
        break
    print(n, end=‘ ‘)

# 输出结果输出结果：0 1 2 3 4 5 6 7 8 9 10

import itertools

# 从10开始，步长为1， 迭代5次
for n in itertools.islice(itertools.count(10), 5):
    if n > 100:
        break
    print(n, end=‘ ‘)
# 输出结果：10 11 12 13 14 

import itertools

# 无限重复传入的序列中的元素
i = 0
for n in itertools.cycle(‘abc‘):
    if i >= 10:
        break
    print(n, end=‘ ‘)
    i += 1
# 输出结果：a b c a b c a b c a

import itertools

# 重复传入的元素
for n in itertools.repeat(‘ABC‘, times=5):
    print(n, end=‘ ‘)
# 输出结果：ABC ABC ABC ABC ABC 

import itertools

# 把一组迭代对象串联起来，形成一个更大的迭代器
chain_list = [c for c in itertools.chain(‘ABC‘, ‘XYZ‘)]
print(chain_list)
# 输出结果：[‘A‘, ‘B‘, ‘C‘, ‘X‘, ‘Y‘, ‘Z‘]

import itertools

for key, group in itertools.groupby(‘AaABbbCCaAAcc‘, key=lambda x: x.upper()):
    print(key, list(group))
# 输出结果：
# A [‘A‘, ‘a‘, ‘A‘]
# B [‘B‘, ‘b‘, ‘b‘]
# C [‘C‘, ‘C‘]
# A [‘a‘, ‘A‘, ‘A‘]
# C [‘c‘, ‘c‘]

import string
import itertools

# ABCDEFGHIJKLMNOPQRSTUVWXYZ
s = string.ascii_uppercase 
# result = list(s)
result = [‘‘.join(t) for t in itertools.product(s, repeat=2) if "AA" <= ‘‘.join(t) <= "AK"]
print(result)
# 输出结果：
# [‘AA‘, ‘AB‘, ‘AC‘, ‘AD‘, ‘AE‘, ‘AF‘, ‘AG‘, ‘AH‘, ‘AI‘, ‘AJ‘, ‘AK‘]