有没有办法在Python中查找和删除字符串中的标点符号？

Question

I have created a function that returns a boolean if a argument contains every letter in the ascii.lowercase string (panagram).

within the code, I am using a for loop to find membership of whitespace and punctuation with the string module methods string.whitespace and string.punctuation .

When testing the for loop, the special characters in string.punctuation portion seems to not be matching the special characters provide from the for loop.

Please provide the reasoning to string.punctuation not working as planned.

import string

def ispanagram(text, alphabet = string.ascii_lowercase):
    """Return boolean if argument is contains every letter in the ascii alphabet"""

    alphabet_list = list(alphabet)    
    letter_set = sorted(set(text.lower()))

    for char in letter_set:
        if char in string.whitespace or char in string.punctuation:
            letter_set.remove(char)

    return letter_set == alphabet_list


ispanagram("The quick brown !fox jumps over the lazy dog")

Answer 1

The main issue is that you're modifying letter_set while iterating over it. This does not work as expected ( explanation ).

To fix, iterate over a copy:

for char in letter_set[:]:

Answer 2

Let me know if this help.

import string
import re

def ispanagram(text, alphabet = string.ascii_lowercase):
    """Return boolean if argument is contains every letter in the ascii alphabet"""

    alphabet_list = list(alphabet)

    # just remove all the special characters including space
    text_only_chars = re.sub(r"[-()\"#/@;:<>{}`+=~|.!?, ]", "", text)

    letter_set = sorted(set(text_only_chars.lower()))

    return letter_set == alphabet_list


print(ispanagram("The quick brown !fox jumps over the lazy dog"))

#### Output ####
True