python元组到字典

问题:python元组到字典

对于元组,t = ((1, 'a'),(2, 'b')) dict(t)返回{1: 'a', 2: 'b'}

有没有一种好的方法{'a': 1, 'b': 2}(交换键和值)?

最终,我希望能够返回1给定'a'2给定'b',也许转换为字典不是最好的方法。

For the tuple, t = ((1, 'a'),(2, 'b')) dict(t) returns {1: 'a', 2: 'b'}

Is there a good way to get {'a': 1, 'b': 2} (keys and vals swapped)?

Ultimately, I want to be able to return 1 given 'a' or 2 given 'b', perhaps converting to a dict is not the best way.


回答 0

尝试:

>>> t = ((1, 'a'),(2, 'b'))
>>> dict((y, x) for x, y in t)
{'a': 1, 'b': 2}

Try:

>>> t = ((1, 'a'),(2, 'b'))
>>> dict((y, x) for x, y in t)
{'a': 1, 'b': 2}

回答 1

稍微简单一些的方法:

>>> t = ((1, 'a'),(2, 'b'))
>>> dict(map(reversed, t))
{'a': 1, 'b': 2}

A slightly simpler method:

>>> t = ((1, 'a'),(2, 'b'))
>>> dict(map(reversed, t))
{'a': 1, 'b': 2}

回答 2

如果您使用的是python 2.7,则更加简洁:

>>> t = ((1,'a'),(2,'b'))
>>> {y:x for x,y in t}
{'a':1, 'b':2}

Even more concise if you are on python 2.7:

>>> t = ((1,'a'),(2,'b'))
>>> {y:x for x,y in t}
{'a':1, 'b':2}

回答 3

>>> dict([('hi','goodbye')])
{'hi': 'goodbye'}

要么:

>>> [ dict([i]) for i in (('CSCO', 21.14), ('CSCO', 21.14), ('CSCO', 21.14), ('CSCO', 21.14)) ]
[{'CSCO': 21.14}, {'CSCO': 21.14}, {'CSCO': 21.14}, {'CSCO': 21.14}]
>>> dict([('hi','goodbye')])
{'hi': 'goodbye'}

Or:

>>> [ dict([i]) for i in (('CSCO', 21.14), ('CSCO', 21.14), ('CSCO', 21.14), ('CSCO', 21.14)) ]
[{'CSCO': 21.14}, {'CSCO': 21.14}, {'CSCO': 21.14}, {'CSCO': 21.14}]

回答 4

如果同一个键有多个值,则以下代码会将这些值附加到与它们的键相对应的列表中,

d = dict()
for x,y in t:
    if(d.has_key(y)):
        d[y].append(x)
    else:
        d[y] = [x]

If there are multiple values for the same key, the following code will append those values to a list corresponding to their key,

d = dict()
for x,y in t:
    if(d.has_key(y)):
        d[y].append(x)
    else:
        d[y] = [x]

回答 5

以下是几种方法:

>>> t = ((1, 'a'), (2, 'b'))

>>> # using reversed function
>>> dict(reversed(i) for i in t)
{'a': 1, 'b': 2}

>>> # using slice operator
>>> dict(i[::-1] for i in t)
{'a': 1, 'b': 2}

Here are couple ways of doing it:

>>> t = ((1, 'a'), (2, 'b'))

>>> # using reversed function
>>> dict(reversed(i) for i in t)
{'a': 1, 'b': 2}

>>> # using slice operator
>>> dict(i[::-1] for i in t)
{'a': 1, 'b': 2}