Question

我有以下两个清单：

Sites = ["iTunes","Google"]
PurchaseTypes = ["Rental","Purchase"]

我如何将所有组合相乘，从而产生：

[
    "iTunesRental",
    "iTunesPurchase",
    "GoogleRental",
    "GooglePurchase"
]

是否有python操作来执行此操作？或者是否需要为每个列表执行for循环？那就是：

combined = []
for s in sites:
    for pt in purchase_types:
        combined.append(s+pt)

Answer 1

使用列表理解：

>>> [a + b for a in Sites for b in PurchaseTypes]
['iTunesRental', 'iTunesPurchase', 'GoogleRental', 'GooglePurchase']

Answer 2

您可以使用itertools.product() -

>>> Sites = [
...         "iTunes",
...         "Google"
...     ]
>>>
>>>
>>> PurchaseTypes = [
...         "Rental",
...         "Purchase"
...     ]
>>>
>>> from itertools import product
>>> l = ['{}{}'.format(*i) for i in product(Sites,PurchaseTypes)]
>>> l
['iTunesRental', 'iTunesPurchase', 'GoogleRental', 'GooglePurchase']

Answer 3

你可以去map-reduce lambda操作。 Map-reduce操作比列表推导慢。但这又是Pythonic编程风格之一。

在您的情况下，可以按如下方式完成：

combined = reduce(lambda a,b:a+b,map(lambda x:map(lambda y:x+y,Sites),PurchaseTypes))

多个字符串列表在一起

3 个答案: