CODEWITHSUNDEEP
javaregex
Dr. Banana
Dr. Banana

Reputation: 435

Regex Ignore Space

With a lot of trying I have managed to create the following regex. I want to use this to prevent the spamming of IP's.

([0-9]{1,3}(\.+|\s+)){3}[0-9]{1,3}

This will catch all the ips if written correctly

for example 8.8.8.8

However it doesn't match "8. 8. 8. 8" or "8 .8 .8 .8" \s*

But I don't seem to get it working, could anyone help me, and explain me where I need to place the \s* to ignore Spaces in between

Regards Jurre

Upvotes: 3

Views: 6627

Answers (2)

Mike Samuel
Mike Samuel

Reputation: 120496

^\s*(?:(?:[2](?:[5][0-5]|[0-4][0-9])|[01]?[0-9][0-9]?)\s*(?:\.\s*(?=[0-9])|(?![0-9]))){4}$

should do it.

To break this down,

  1. (?:[2](?:[5][0-5]|[0-4][0-9])|[01]?[0-9][0-9]?) matches any non-negative decimal integer of at most three digits in the range [0,255].
  2. \s* matches zero or more spaces.
  3. (?:\.\s*(?=[0-9])|(?![0-9])) matches a dot and space when followed by more digits or the end of the digits
  4. {4} requires four repetitions of this whole

To make it more readable, you can break it down:

String INT_IN_0_TO_255 = "(?:[2](?:[5][0-5]|[0-4][0-9])|[01]?[0-9][0-9]?)";
String OPTIONAL_SPACE = "\\s*";
String DOT_BEFORE_MORE_NUMBERS = "(?:\.\s*(?=[0-9])|(?![0-9]))";
String NUMERIC_IP_ADDRESS =
   "^"
   + OPTIONAL_SPACE
   + "(?:"
   + INT_IN_0_TO_255
   + OPTIONAL_SPACE
   + DOT_BEFORE_MORE_NUMBERS
   + "){4}$";

Upvotes: 1

anubhava
anubhava

Reputation: 784998

You can use this regex to allow white spaced anywhere in an IP address:

^\s*([0-9]{1,3}\s*\.\s*){3}[0-9]{1,3}\s*$

Online Demo: http://regex101.com/r/zZ9kH6

Upvotes: 3

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