如何同时使用 isalpha( ) 和 isdigit( ) 过滤掉不是字母或数字的内容？答案

【问题标题】：How to use both isalpha( ) and isdigit( ) to filter out what isn't a letter or digit?如何同时使用 isalpha( ) 和 isdigit( ) 过滤掉不是字母或数字的内容？
【发布时间】：2020-11-19 21:47:49
【问题描述】：

我需要使用 .isalpha() 和 .isdigit() 过滤掉所有不是字母或数字的内容。
目前正在做定义和 .replace()。

This is my program

【问题讨论】：

这两个功能有必要用吗？
你能发布你的代码吗？顺便说一句，isalnum 有一个函数
@KarinaK 是的，有人告诉我同时使用 isalpha() 和 is digit()。
exit = False takeout =":.;!@#$%^&*()}{|\+=" + " " while exit == False: data = input(("Enter设置或按 E/e 退出：")) data = data.lower() for i in takeout : data = data.replace(i,"") newdata = data[::-1] print("输入向后打印is: ", newdata,"\n") if len(data)

标签： python string loops palindrome isalpha

【解决方案1】：

def remove_special_chars(string):
    output = []
    for c in string:
        if c.isalpha() or c.isdigit();
            output.append(c)
    return ''.join(output)

【讨论】：

【解决方案2】：

您可以通过以下方式轻松实现：

from sets import Set

allowed_chars = Set('0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ')
validationString = 'inv@lid'

if Set(validationString).issubset(allowed_chars):
    return validationString # nothing to remove from this string
else:
    return ''.join(i for i in validationString if Set(i).issubset(allowed_chars))

【讨论】：

不用手动输入所有字母和数字，只需使用string.ascii_letters和string.digits：docs.python.org/3/library/string.html

【解决方案3】：

使用正则表达式拆分和过滤以及isdigit和isalpha

 sentence ="1 I have bought several of the Vitality canned dog food products and have found them all to be of good quality. huh? The product looks more like a stew than a processed meat and it smells better-looks better. My Labrador is finicky-pampered and she appreciates this product better than most."
 sentence=sentence.lower()
 words=re.split("[, |-|\?|\!|\.]",sentence)
 words=filter(lambda w: ((w.isdigit() or w.isalpha()) and len(w)>0),words)
 print(*words)

输出：

  1 i have bought several of the vitality canned dog food products and have found them all to be of good quality huh the product looks more like a stew than a processed meat and it smells better my labrador is and she appreciates this product better than most

【讨论】：