Python - 从字符串中移除不需要的字符

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Python 是一种非常常用的程序，用于各种目的，例如 Web 开发、数据科学、机器学习，以及执行各种自动化流程。在任何应用领域工作时，我们都必须处理一个共同的东西，即字符串。因此，在本文中，我们将学习如何从字符串中移除不需要的字符。

替换

在这种方法中，我们只需指定不需要的元素，然后移除该元素，并在字符串中留下一个空位。我们可以通过以下示例更好地理解它

示例

def unwanted_string_words(data, sentence):  #Input is provided
    for sent in sentence:   #Check different characters in string
        data = data.replace(sent, '')   #Remove unwanted characters from string
    return data 

# Example
whole_string = "Hi! My Name Is, John"
to_be_removed = "!,"
final_string =unwanted_string_words(whole_string, to_be_removed)
print(final_string)  

输出

以上代码的输出如下所示

Hi My Name Is John 

re 模块

在这种方法中，我们将使用正则表达式模块从字符串中移除字符。我们可以从以下示例中了解其用法

示例

import re   # Do not forget to import the re module or else error might occur

def unwanted_string_words(data, sentence):   # The input is provided
    pattern = "[" + re.escape("".join(sentence)) + "]"  #We will join all the characters using re.escape
    return re.sub(pattern, "", data)   # We will then use re.sub to remove the unwanted characters

# Example
whole_string = "Hi! My Name Is, John"
to_be_removed = "!,"
final_string =unwanted_string_words(whole_string, to_be_removed)
print(final_string)  

输出

以上示例的输出如下所示

Hi My Name Is John 

列表推导式

通过这种方法，我们将创建一个仅包含所需字符的新列表，在从原始字符串中移除所有不需要的字符之后。我们可以通过以下示例清楚地了解它

示例

def unwanted_string_words(data, sentence):   #The input is provided
   return ''.join([sent for sent in data if sent not in sentence])   # All the characters in the string are checked and the characters which are not to be removed sre moved to a new list and some characters are removed.

# Example
whole_string = "Hi! My Name Is, John"
to_be_removed = "!,"
final_string =unwanted_string_words(whole_string, to_be_removed)
print(final_string)  

输出

以上示例的输出如下所示

Hi My Name Is John 

translate 方法

这是一种非常有用的方法，可以从字典列表中移除字符。要移除的字符在转换表中指定，并相应地移除。以下是如何使用 translate 方法移除字符的示例

示例

def unwanted_string_words(data, sentence):  #The input of string is provided
    translation_table_characters = str.maketrans('', '', ''.join(sentence))    # With the help pf str.maketrans a translation table is made and the characters to be removed are specified     
    return data.translate(translation_table_characters)  #The str.translate is used to remove the characters and provide an empty space

# Example
whole_string = "Hi! My Name Is, John"
to_be_removed = "!,"
final_string =unwanted_string_words(whole_string, to_be_removed)
print(final_string) 

输出

以上示例的输出如下所示

Hi My Name Is John 

filter 函数

顾名思义，在这种方法中，我们将指定一些过滤器以从我们的字符串中移除一些字符。这是从字符串中移除字符的最简单方法之一。我们可以通过以下示例更清楚地了解它

示例

def unwanted_string_words(data, sentence):  # The input of string is given
    unwanted_string_words = filter(lambda sent: sent not in sentence, data)  #Filter will check all the characters of the string
    # Lambda will be used to look for the unwanted characters in the whole string
    return ''.join(unwanted_string_words)  #After removing the unwanted characters, the remaining characters are moved to a new list 

# Example
whole_string = "Hi! My Name Is, John"
to_be_removed = "!,"
final_string =unwanted_string_words(whole_string, to_be_removed)
print(final_string) 

输出

以上示例的输出如下所示

Hi My Name Is John 

列表 & 连接

在这种方法中，整个字符串被转换为字符，然后检查所有字符，并从列表中移除所有不需要的字符。我们可以通过以下示例更好地理解它

示例

def unwanted_string_words(data, sentence):  # The input of string is provided 
    unwanted_string_words = [sent for sent in data if sent not in sentence]  # List comprehension will be used to check each characters and the unwanted ones will be removed
    return ''.join(unwanted_string_words)  #The remaining characters will be joined to form a string

# Example
whole_string = "Hi! My Name Is, John"
to_be_removed = "!,"
final_string =unwanted_string_words(whole_string, to_be_removed)
print(final_string) 

输出

以上示例的输出如下所示

Hi My Name Is John 

结论

程序中存在的字符串的编辑是程序员遵循的常见过程。因此，了解以上所有方法对于成为一名高效快捷的程序员至关重要。可以参考本文了解许多从字符串中移除字符的不同方法。