正则表达式对数字的验证

Question

This regex expression that I have validate the situation below:

Correct input:

1. 12345678,12345678,12345678
2. *space*12345678 , 12345678 , 12345678 , 12345678
3. 12345678,12345678,*space*
4. 12345678
5. *space*12345678,
6. 12345678,

Result: return true(regex expression is working correctly for situations above.)

wrong input:

1. 1234567812345678

Result: return true (should be false)

For wrong input it should be returning false , but it return true. what should i do to validate for the wrong input?

   var validate_commas = /^(\s*\d{8}\s*[,]?\s*)*$/;

Thank you

Answer 1

See Ambiguity in description for more details on why your question is ambiguous, and how that affects the answers you get.

I assume spaces (ASCII 32) are arbitrarily allowed:

• At the start of the string
• At the end of the string
• Before and after comma.

I assume that you want to disallow horizontal tabs, new lines, carriage returns and other whitespace characters matched by \\s , and only allow space (ASCII 32) to be freely specified.

The BNF grammar with the above assumptions is:

<DIGIT>  ::= "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9"
<NUMBER> ::= <DIGIT> {8}
<SPACE>  ::= " "
<TOKEN>  ::= <SPACE>* <NUMBER> <SPACE>*
<LIST>   ::= <TOKEN> ( "," <TOKEN> )* [ "," <SPACE>* ]

With the grammar above, it is easy to write the regex solution:

var regex = /^ *\d{8} *(?:, *\d{8} *)*(?:, *)?$/;

Ambiguity in description

Rather than showing examples of what string you want to match, as suggested, your should specify a grammar for your input. Examples may not cover all the cases, and the answerer usually assumes "don't care" or make up some assumptions for the cases not stated in the examples.

Answer 2

Does removing the optional comma help?

var validate_commas = /^(\s*\d{8}\s*)(,\s*\d{8}\s*)*,?$/;

Without clearer information, this is the best that can be done without making more assumptions... eg will there ever only be one numbers and no commas?

Answer 3

This should work

var validate_commas = /^(\s*\d{8}\s*(?:$|,\s*))*$/;

It will take one or more instances of 8 numeric characters followed by the end of the string or another comma.

Or alternatively if you do not want the expression to match an empty line, change the last quantifier to the one or more character: +

var validate_commas = /^(\s*\d{8}\s*(?:$|,\s*))+$/;

Will return true on the following inputs:

12345678,12345678,12345678
*space*12345678 , 12345678 , 12345678 , 12345678
12345678,12345678,*space*
12345678
*space*12345678,
12345678,

Will return false on the following inputs:

1234567812345678
sdsdsfsd
12345678, 12345678 12345678

I hope this helps.

Answer 4

You could try something like this:

var validate_commas = /^\s*\d{8}(\s*,\s*(?:\d{8})?)*$/;

Much like the other suggestions, except it makes the additional numbers optional, thus allowing for 12345678, etc.

Answer 5

You mean the comma is not optional between numbers?

Try this:

var validate_commas = /^(\s*\d{8}\s*)(,\s*\d{8}\s*)*$/;

Incidentally this doesn't accept the empty string which your example did. Not sure if you really wanted that.