python三种特殊的迭代

字典的迭代

d = {'a': 1, 'b': 2, 'c': 3}
for key in d:
	print(key)

for value in d.values():
	print(value)

for k,v in d.items():
	print

索引，元素对

for i, value in enumerate(['A', 'B', 'C']):
	print(i, value)
	
"""
0 A
1 B
2 C
"""

序列解包

for x, y in [(1, 1), (2, 4), (3, 9)]:
	print(x, y)

"""
1 1
2 4
3 9
"""