Python 从字符串中删除不需要的字符

Python是一个非常常用的程序，用于不同的目的，如网站开发、数据科学、机器学习，以及执行自动化的不同过程。在任何应用领域工作时，我们都必须处理一个共同的东西，称为字符串。因此，在本文中，我们将学习如何从字符串中删除不需要的字符。

替换

在这种方法中，我们只需指定不需要的元素，然后该元素就会被删除，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

以上代码的输出结果如下：

Hi My Name Is John

re模块

在这个方法中，我们将使用正则表达式模块从字符串中删除字符。我们可以通过以下示例来理解它的用法：

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

以上示例的输出将如下所示：

Hi My Name Is John

列表推导

通过这种方法，我们将从原始字符串中删除所有不需要的字符，并仅创建一个包含所需字符的新列表。我们可以通过以下示例清楚地理解：

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

上面提供的示例的输出如下：

Hi My Name Is John

翻译方法

这是一种非常有用的方法，可以从一组字典中移除字符。要移除的字符由翻译表指定，并会相应地被移除。通过使用翻译方法来移除字符的示例如下：

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

上述示例的输出如下：

Hi My Name Is John

过滤函数

正如其名称所示，这种方法中我们将指定一些过滤器来删除字符串中的某些字符。这是从字符串中删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理解：

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

上述示例的输出结果如下：

Hi My Name Is John

列表与连接

在这种方法中，将整个字符串划分为字符，然后检查所有字符，并从列表中删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)