Help with Javascript regular expression

fletch

I'm trying to create a Javascript regular expression that will accept the following

RER or rer followed by a letter [A,B,C,or no letter] followed by [0-9]{1,9}

I hope that make sense,

So far I have

var filter = /^([R,r])+([E,e])+([R,r])+([A,a,B,c,C,c])+([0-9]{1,9})$/;

I just don't know how to get it to recognise if there is no letter following the RER, i.e I can't get it to recognise RER1

Any help much appreciated

fletch

Think I have it, added a question mark to the filter
var filter = /^([R,r])+([E,e])+([R,r])+([A,a,B,c,C,c]?)+([0-9]{1,9})$/;

Hobbes

/^rer[A-C]?\d{1,9}/ig

Inspector Gadget

If you're okay with the regex matching odd combinations of cases (such as 'ReRa1') then Hobbes' regex is fine, with a couple of slight modifications so that it can be use to retrieve the match:

/^(rer[A-C]?\d{1,9})$/ig

If you need it to match either exactly 'RER' or 'rer', then a letter between 'A' and 'C' (either case), and then between one and nine digits, try this:

/^((?:RER|rer)[A-Ca-c]?\d{1,9})$/ig

Gadget

Hobbes

/^(rer[A-C]?\d{1,9})$/ig

That one will only work if the line is only the requested match. I took it to mean he is looking for all lines beginning with.

/^((?:RER|rer)[A-Ca-c]?\d{1,9})$/ig

Second one won't work because your setting it to ignore case. So it will still match stuff like "rEr" for example. To fix that you can remove the "i". Again it is an exact line match only. To stop that you remove the "$".

If the match is needed not at the start of the line then remove the "^".

Inspector Gadget

Hobbes wrote: »

Second one won't work because your setting it to ignore case. So it will still match stuff like "rEr" for example. To fix that you can remove the "i". Again it is an exact line match only. To stop that you remove the "$".

Yep, typo on my part

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