Question

我有一些列表，我想从中过滤元素。这是列表：

list1 = ['Little Mary had a lamb', 'the horse is black', 'Mary had a cat']
list2 = ['The horse is white', 'Mary had a dog', 'The horse is hungry']
listn = ...

在以下示例中，假设我知道一个相关的单词或表达， Mary 或 horse 。我想获得一个新列表，如果这些项包含术语或搜索的表达式，将从其他列表中提取哪些项。例如。：

listMary = ['Little Mary had a lamb', 'Mary had a cat', 'Mary had a dog'] 
listHorse = ['the horse is black', 'The horse is white', 'The horse is hungry']
listn = ...

不要担心我的数据更复杂;）

我知道我应该使用正则表达式模块，但在这种情况下我无法找到以哪种方式。我在Stack Overflow上尝试了一些搜索，但我不知道如何清楚地表达问题所以我找不到任何有用的东西。

Answer 1

可能是这样的：

>>> a = ['Little Mary had a lamb', 'the horse is black', 'Mary had a cat']
>>> b = ['The horse is white', 'Mary had a dog', 'The horse is hungry']
>>> [sent for sent in a+b if 'Mary' in sent]
['Little Mary had a lamb', 'Mary had a cat', 'Mary had a dog']

或者如果您更喜欢使用正则表达式：

>>> import re
>>> [sent for sent in a+b if re.search("horse", sent)]
['the horse is black', 'The horse is white', 'The horse is hungry']

Answer 2

使用列表推导的条件子句。

[x for x in L if regex.search(x)]

Answer 3

您不一定需要正则表达式模块：

word = 'horse'
result = []
for l in [list1, list2, list3]:
    for sentence in l:
        if word in sentence:
            result.append(sentence)

Answer 4

用户内置函数filter它将快速有效。

def f(x): 
    return x % 2 != 0 and x % 3 != 0

filter(f, range(2, 25))

所以这里def f将需要一个arg并进行匹配并返回true false并且您将获得结果列表。

谢谢

从列表中提取一些项目以构建新列表

4 个答案: