什么是非字母数字字符？

Characters are used to express letters, numbers, signs, etc. Characters are categorized as alphanumeric and non-alphanumeric characters. Alphanumeric characters are consist of alphabet characters and numeric characters. Other than alphanumeric characters are called as non-alphanumeric characters.

字符用于表示字母，数字，符号等。字符分为字母数字字符和非字母数字字符。 字母数字字符由字母字符和数字字符组成。 字母数字字符以外的字符称为非字母数字字符。

字母数字字符 (Alphanumeric Characters)

Alphanumeric characters consist of alphabet and numeric characters. Alphabet characters can be lower case or upper case.

字母数字字符由字母和数字字符组成。 字母字符可以是小写或大写。

非字母数字字符 (Non-Alphanumeric Characters)

Non-Alphanumeric characters are except alphanumeric characters. space, percent sign, underscore, pipe, colon, semicolon, etc are non-alphanumeric characters. They can be also categorized as punctuation characters, symbol characters, etc.

非字母数字字符是字母数字字符以外的字符。 空格，百分号，下划线，竖线，冒号，分号等均为非字母数字字符。 它们也可以分为标点符号，符号字符等。

1. (blank space)
2. ~ (tilde)
3. ` (grave accent)
4. ! (exclamation mark)
5. @ (at)
6. # (pound)
7. $ (dollar sign)
8. % (percent)
9. ^ (carat)
10. & (ampersand)
11. * (asterisk)
12. ( (open parenthesis)
13. ) (close parenthesis)
14. _ (underscore)
15. – (hyphen)
16. + (plus sign)
17. = (equals)
18. { (open brace)
19. } (close brace)
20. [ (open bracket)
21. ] (close bracket)
22. | (pipe)
23. \ (backslash)
24. : (colon)
25. ; (semicolon)
26. < (less than)
27. , (comma)
28. > (greater than)
29. . (period)
30. ? (question mark)
31. / (forward slash)