python学习九

d = {'a': 1, 'b': 2, 'c': 3}

for key in d:
    print(key)

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

# 迭代key、value
for k, v in d.items():
    print(k,v)
    
# 迭代索引和元素本身
for i, value in enumerate(['A', 'B', 'C']):
    print(i, value)
    
# 引用了两个变量
for x, y in [(1, 1), (2, 4), (3, 9)]:
    print(x, y)