Ip address regular expression, ip address Regular Expression

Ip address regular expression, ip address Regular Expression

Regular expressions are used to format and match characters, and a single command is used to complete the judgment.

 

IP address format: x. x

X indicates 0 ~ Number of 255

In three cases

A. 250-255: features: the number of three digits, the number of hundred digits is 2, the number of digits is 5, and the number of digits is 0 ~ 5. You can use a regular expression as follows: 25 [0-5]
B. 200-249: features: the number of three digits, the number of hundred digits is 2, and the number of digits is 0 ~ 4. The single digit is 0 ~ 9, which can be written as: 2 [0-4] \ d
C. 0-199: this can be further split, Which is simpler and clearer.
C. a. 0-9: features: one-digit, with a single digit ranging from 0 to 9 ~ 9. The regular expression can be written as \ d.
C. B. 10-99: feature: two-digit, one to ten ~ 9, with a single digit ranging from 0 ~ 9. The regular expression can be written as [1-9] \ d.
C. c. 100-199: features: three digits, 1 for hundreds of digits, and 0 for ten digits ~ 9, with a single digit ranging from 0 ~ 9. The regular expression can be written as 1 \ d {2}

Therefore, the regular expression 0-99 can be written into [1-9]? \ D, then 0-199 can be written as (1 \ d {2}) | ([1-9]? \ D), So 0 ~ The Regular Expression of 255 can be written as (25 [0-5] | 2 [0-4] \ d | (1 \ d {2 }) | ([1-9]? \ D )))
Finally, you can use {3} to repeat the previous three segments and use the same match again in section 4th to obtain the regular expression of the IP Address:

^((?:(?:25[0-5]|2[0-4]\d|((1\d{2})|([1-9]?\d)))\.){3}(?:25[0-5]|2[0-4]\d|((1\d{2})|([1-9]?\d))))$

The meaning of each symbol, refer to MSDN

Reference source webpage

IP address Regular Expression

Back to jiemy_1987
Your expression is too much. Think about it again.
If your expression has more than 6 numbers, an error is returned. If each segment does not have 1 or 2, an error is returned.
Try it.
Var str = '6. 6.6.6 ';
Var str2 = '55. 55.55.55 ';

Below is my:
$ Patten = '/^ ([1-9] | ([1-9] \ d) | (1 \ d) | (2 ([0-4] \ d | 5 [0-5]) \.) (d | ([1-9] \ d) | (1 \ d) | (2 ([0-4] \ d | 5 [0-5]) \.) {2} ([1-9] | ([1-9] \ d) | (1 \ d) | (2 ([0-4] \ d | 5 [0-5]) $ /';

It's a little bloated, but it can definitely be used.
Ip: 1.0.0.1 to 255.255.255.255
Each segment cannot start with "0"
---------------------------------------
There are so many people copying this year.
Modified
$ Patten = '/^ ([1-9] | ([1-9] \ d) | (1 \ d) | (2 ([0-4] \ d | 5 [0-5]) \.) ([1-9] | ([1-9] \ d) | (1 \ d) | (2 ([0-4] \ d | 5 [0-5]) \.) {2} ([1-9] | ([1-9] \ d) | (1 \ d) | (2 ([0-4] \ d | 5 [0-5]) $ /';
I'm sorry.

How to Write a regular expression for an IP address?

The Regular Expression of the IP Address:
^ (25 [0-5] | 2 [0-4] [0-9] | [0-1] {1} [0-9] {2} | [1 -9] {1} [0-9] {1} | [1-9]) \\. (25 [0-5] | 2 [0-4] [0-9] | [0-1] {1} [0-9] {2} | [1- 9] {1} [0-9] {1} | [1-9] | 0) \\. (25 [0-5] | 2 [0-4] [0-9] | [0-1] {1} [0-9] {2} | [1- 9] {1} [0-9] {1} | [1-9] | 0) \\. (25 [0-5] | 2 [0-4] [0-9] | [0-1] {1} [0-9] {2} | [1- 9] {1} [0-9] {1} | [0-9]) $