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

递归分割: s =字符串;Chars =要删除的字符

def strip(s,chars):
if len(s)==1:
    return "" if s in chars else s
return strip(s[0:int(len(s)/2)],chars) +  strip(s[int(len(s)/2):len(s)],chars)

例子:

print(strip("Hello!","lo"))    #He!

下面一个. .没有使用正则表达式的概念..

ipstring ="text with symbols!@#$^&*( ends here"
opstring=''
for i in ipstring:
    if i.isalnum()==1 or i==' ':
        opstring+=i
    pass
print opstring

line = line.translate(None, " ?.!/;:")

>>> line = "abc#@!?efg12;:?"
>>> ''.join( c for c in line if  c not in '?:!/;' )
'abc#@efg12'

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