Python 按单词的位置选择字符串

对于以下元组

mysentence = 'i have a dog and a cat', 'i have a cat and a dog', 'i have a cat', 
             'i have a dog'

---

如何只选择字符串“我有一只猫”，“我有一只狗”，也就是说，排除了中间有单词“狗”或“猫”的字符串。

如果该字符串应该用一个特定的短语结束，那么这将完成任务：

phases = ("I have a cat", "I have a dog")
for sentence in mysentence:
    for phase in phases:
        if sentence.lower().endswith(phase.lower()):
            print(sentence)

---

如果字符串应以特定短语结尾，则此操作将完成：

phases = ("I have a cat", "I have a dog")
for sentence in mysentence:
    for phase in phases:
        if sentence.lower().endswith(phase.lower()):
            print(sentence)

---

你可以用正则表达式来匹配你不想要的句子

我们可以建立如下模式：

我们想和狗或猫-狗-猫比赛 后跟空格，即不在行的末尾 因此，我们的代码如下所示：

>>> mysentence = ('i have a dog and a cat', 'i have a cat and a dog', 'i have a cat', 'i have a dog')
>>> import re                                                                   
>>> pattern = re.compile("(dog|cat) ")
>>> [x for x in mysentence if not pattern.search(x)]                            
['i have a cat', 'i have a dog']

---

你可以用正则表达式来匹配你不想要的句子

我们可以建立如下模式：

我们想和狗或猫-狗-猫比赛 后跟空格，即不在行的末尾 因此，我们的代码如下所示：

>>> mysentence = ('i have a dog and a cat', 'i have a cat and a dog', 'i have a cat', 'i have a dog')
>>> import re                                                                   
>>> pattern = re.compile("(dog|cat) ")
>>> [x for x in mysentence if not pattern.search(x)]                            
['i have a cat', 'i have a dog']

---

您可以使用正则表达式来实现这一点。regex.+dog | cat.+将匹配一个或多个字符，后跟dog或cat，然后再匹配一个或多个字符。然后可以使用筛选器查找与此正则表达式不匹配的字符串：

import re
regex.compile(r'.+(dog|cat).+')
sentence = 'i have a dog and a cat', 'i have a cat and a dog', 'i have a cat', 
           'i have a dog'
filtered_sentence = filter(lambda s: not regex.match(s), sentence)

---

您可以使用正则表达式来实现这一点。regex.+dog | cat.+将匹配一个或多个字符，后跟dog或cat，然后再匹配一个或多个字符。然后可以使用筛选器查找与此正则表达式不匹配的字符串：

import re
regex.compile(r'.+(dog|cat).+')
sentence = 'i have a dog and a cat', 'i have a cat and a dog', 'i have a cat', 
           'i have a dog'
filtered_sentence = filter(lambda s: not regex.match(s), sentence)

---

可能起作用的最简单的事情：

In [10]: [phrase for phrase in mysentence if not ' and ' in phrase]
Out[10]: ['i have a cat', 'i have a dog']

---

可能起作用的最简单的事情：

In [10]: [phrase for phrase in mysentence if not ' and ' in phrase]
Out[10]: ['i have a cat', 'i have a dog']

---

您可以使用regexp或string方法

我看到另一个是用正则表达式回答的，所以我尝试了string方法：with string.find，您将获得子字符串在string中的位置。然后检查它是否在句子的中间。

def filter_function(sentence, words):
    for word in words:
        p = sentence.find(word)
        if p > 0 and p < len(sentence) - len(word):
            return 0
    return 1

for sentence in mysentence:
    print('%s: %d' % (sentence, filter_function(sentence, ['dog', 'cat'])))

---

当句子中只有“cat”时，您还必须定义要执行的操作。

您可以使用regexp或string方法

def filter_function(sentence, words):
    for word in words:
        p = sentence.find(word)
        if p > 0 and p < len(sentence) - len(word):
            return 0
    return 1

for sentence in mysentence:
    print('%s: %d' % (sentence, filter_function(sentence, ['dog', 'cat'])))

for items in mysentence:
    if (items.find("dog")>=0)^(items.find("cat")>=0):
        print(items)

我看到另一个是用正则表达式回答的，所以我尝试了string方法：with string.find，您将获得子字符串在string中的位置。然后检查它是否在句子的中间。

def filter_function(sentence, words):
    for word in words:
        p = sentence.find(word)
        if p > 0 and p < len(sentence) - len(word):
            return 0
    return 1

for sentence in mysentence:
    print('%s: %d' % (sentence, filter_function(sentence, ['dog', 'cat'])))

你们还必须定义当你们的句子中只有“猫”时该做什么

def filter_function(sentence, words):
    for word in words:
        p = sentence.find(word)
        if p > 0 and p < len(sentence) - len(word):
            return 0
    return 1

for sentence in mysentence:
    print('%s: %d' % (sentence, filter_function(sentence, ['dog', 'cat'])))

for items in mysentence:
    if (items.find("dog")>=0)^(items.find("cat")>=0):
        print(items)

您只需要一个xor运算符和find函数。不需要进口

---

您只需要一个xor运算符和find函数。不需要导入“狗”或“猫”之类的句子吗？用“狗”或“猫”这样的句子做什么？OP想排除中间有单词“狗”或“猫”的字符串，所以你的答案会失败。例如，你有一只猫，我有一只狗。OP想排除中间有单词狗或猫的字符串，所以你的答案会失败，例如你有一只猫，我有一只狗。