每天CookBook之Python-009

• 并集、差集、合集操作
• 推导

>>> a = {
...     'x': 1,
...     'y': 2,
...     'z': 3
... }
>>> b = {
...     'w': 10,
...     'x': 11,
...     'y': 2
... }
>>> print(a.keys() & b.keys())
{'x', 'y'}
>>> print(a.keys() - b.keys())
{'z'}
>>> print(a.items() & b.items())
{('y', 2)}
>>> c = {key: a[key] for key in a.keys() - {'z', 'w'}}
>>> print(c)
{'x': 1, 'y': 2}