JavaScript正则表达式不能替换'@'字符

Question

I am new to JavaScipt and testing a regular Expression and is working on below use case -

Requirement - Replace every character with '#' that is NOT FROM BELOW LIST -

• Number
• Character (upper or lower case)
• Any special character except -> comma, dot, square brackets, forward slash, single Quote

Please find my code below -

    var replacedStr = str.replace(/[^a-zA-Z0-9'.-\[\], ]/g,"#");

Output for various values of str are -

   str = "hello_";
   replacedStr is hello#
   _______________________
   str = "hello@_";
   replacedStr is hello@#

I wanted to know why '@' isnot being replaced from above regex.

The same behavior is with characters - underScore, question-Mark, Angular brackets.

Please guide.

Thanks,

Vibhav

Answer 1

In your original regex, your dash (hyphen) is being interpreted as a range:

[^a-zA-Z0-9'.-\[\], ]

This is being intepreted as the range of characters from dot . until opening bracket [ , which includes the at symbol. If you move the hyphen to the very end of the negated character class, the regex will work as intended:

 str = "hello@_"; str = str.replace(/[^a-zA-Z0-9'.\\[\\], -]/g,"#"); console.log(str); 

Answer 2

Couple of mistakes in your reg-ex you have to put '-' in front of charachter class (or at last).

Below reg-ex will do the trick

/[^.,\[\]\\'a-zA-Z0-9]/g

you can use online testers like http://www.regexpal.com/ to check regex's

Answer 3

连字符将作为范围，因此您需要向其添加一个转义序列。

str.replace(/[^a-zA-Z0-9'.\-\[\]]/g,"#");