RegEx for validating specific input

Question

The input accepts data in format: %'letter' separator %'letter' and so on.

The separator can be: space, tab, colon or new line

Example:

%d %F %S   
or     
%d:%F:%S    
or    
%d:%F
%S

where the character after the '%' can be any letter

You cannot write something like:

%dddd %F %S
or 
%%d %F %S

So far I have done this:

^((%([a-zA-Z]){1})+\s?|:)+$

Any help will be appreciated.

Nicola Miotto · Accepted Answer · 2013-11-13 13:45:17Z

2

How about

^((%[A-z])(\s|:))*(%[A-z])$

answered Nov 13, 2013 at 13:38

Nicola Miotto

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2 Comments

This allows: %d%d which is not valid

I've added the line begin and line termination, now it should work

rzymek · Accepted Answer · 2013-11-13 13:46:40Z

1

You can go with this

(%[a-zA-Z][ \t\n;])*%[a-zA-Z]

Regular expression visualization

But I'd suggest passing an case-insensitive flag to your matcher. Then the expression can be shortened to

(%[a-z][ \t\n;])*%[a-z]

answered Nov 13, 2013 at 13:39

rzymek

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This allows to have %d %d%d. Every pair of %'letter' should have a separator between them, except the last one