I need to generate a regExr for the below String pattern.
A:B:C:D
where A should contain only Strings and B can contain both String and a digits and C should be a String and D should only be the digits.
I created RegExr myself and its working.
[a-zA-Z]+(:)+[a-zA-Z1-9]+(:)+[a-zA-Z]+(:)+[1-9]+
But is there a better regExr for the pattern I want something bit shorter than mine? Or mine is ok?
I am using Java8.
Use \d instead 1-9(if 0 is permitted).
You can use \d for digits and if you don't mind accepting the underscore you can also use the \w for the [a-zA-Z].
Your Regexp could become:
[\w]+:[\w\d]+:[\w]+:[\d]+
Your regex code looks completely fine if you have to avoid 0 and _ otherwise you can use above examples. If you want to pass it as parameter then try assinging it to a string, that will be more convinient(which I haven't tried yet!).
Your RegEx only captures the :.
This RegEx works for "Hello:hel35a:ahelkj:684579" and captures the whole String.
([A-Za-z]+:(?:[A-Za-z]|\d)+:[A-Za-z]+:\d+)
([A-z]*:(?:[A-z]|\d)*:[A-z]*:\d*) also matches _:_:_: , ::: or [\]^_:_:_:` because [a-Z] matches more than you think. The OP commented that it should not match underscores. Using the asterix * means repeat zero or more times. That means that you made everything optional except the colons :([A-z]*:(?:[A-z]|\d)*:[A-z]*:\d*) does match _:_:_: because the \d* matches zero or more times. You can check the link.You Expression looking good. If you want more regEx operations use this site it is very helpful txt2re
A:::B:C:D, and it wouldn't match A:B:C:0You might use a word boundary \b if you don't' want your match to be part of a larger match. (Or use anchors ^ and $ to assert the start and end of the string)
For example a:1a:b:0 would match, but a:1a:b:0a does not because it has an a at the end.
To match a digit 0-9 you could use \d and to match a single colon you could just use : without a quantifier + or a capturing group ()
Your regex could look like this:
note the case insensitive flag /i in the demo to use [a-z] instead of [A-Za-z]
\b[a-z]+:[a-z\d]+:[a-z]+:\d+\b
Java:
(:)+means one-or-more colons, right? Seems you want exactly one colon, and you don't need to capture it. Also, a0is a digit too, you know. So this is what you need:[a-zA-Z]+:[a-zA-Z0-9]+:[a-zA-Z]+:[0-9]+(?i)[a-z]+:[a-z0-9]+:[a-z]+:[0-9]+