我试图使用Python从字符串中删除特定字符。这是我现在使用的代码。不幸的是,它似乎对字符串没有做任何事情。

for char in line:
    if char in " ?.!/;:":
        line.replace(char,'')

我如何正确地做到这一点?


当前回答

提问者几乎就说到了。像Python中的大多数事情一样,答案比您想象的要简单。

>>> line = "H E?.LL!/;O:: "  
>>> for char in ' ?.!/;:':  
...  line = line.replace(char,'')  
...
>>> print line
HELLO

你不需要做嵌套的if/for循环,但你确实需要单独检查每个字符。

其他回答

>>> s = 'a1b2c3'
>>> ''.join(c for c in s if c not in '123')
'abc'

这是我的Python 2/3兼容版本。因为翻译api已经改变了。

def remove(str_, chars):
    """Removes each char in `chars` from `str_`.

    Args:
        str_: String to remove characters from
        chars: String of to-be removed characters

    Returns:
        A copy of str_ with `chars` removed

    Example:
            remove("What?!?: darn;", " ?.!:;") => 'Whatdarn'
    """
    try:
        # Python2.x
        return str_.translate(None, chars)
    except TypeError:
        # Python 3.x
        table = {ord(char): None for char in chars}
        return str_.translate(table)

#对于目录中的每个文件,重命名文件名

   file_list = os.listdir (r"D:\Dev\Python")

   for file_name in file_list:

       os.rename(file_name, re.sub(r'\d+','',file_name))

试试这个:

def rm_char(original_str, need2rm):
    ''' Remove charecters in "need2rm" from "original_str" '''
    return original_str.translate(str.maketrans('','',need2rm))

这个方法在python3中很有效

字符串方法replace不会修改原始字符串。它保留原始文件并返回修改后的副本。

你需要的是这样的:line = line.replace(char, ")

def replace_all(line, )for char in line:
    if char in " ?.!/;:":
        line = line.replace(char,'')
    return line

然而,每次删除一个字符都创建一个新的字符串是非常低效的。我推荐以下方法:

def replace_all(line, baddies, *):
    """
    The following is documentation on how to use the class,
    without reference to the implementation details:

    For implementation notes, please see comments begining with `#`
    in the source file.

    [*crickets chirp*]

    """

    is_bad = lambda ch, baddies=baddies: return ch in baddies
    filter_baddies = lambda ch, *, is_bad=is_bad: "" if is_bad(ch) else ch
    mahp = replace_all.map(filter_baddies, line)
    return replace_all.join('', join(mahp))

    # -------------------------------------------------
    # WHY `baddies=baddies`?!?
    #     `is_bad=is_bad`
    # -------------------------------------------------
    # Default arguments to a lambda function are evaluated
    # at the same time as when a lambda function is
    # **defined**.
    #
    # global variables of a lambda function
    # are evaluated when the lambda function is
    # **called**
    #
    # The following prints "as yellow as snow"
    #
    #     fleece_color = "white"
    #     little_lamb = lambda end: return "as " + fleece_color + end
    #
    #     # sometime later...
    #
    #     fleece_color = "yellow"
    #     print(little_lamb(" as snow"))
    # --------------------------------------------------
replace_all.map = map
replace_all.join = str.join