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Regular Expressions

 
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Hi All,

We need to write a regular expression which can accept a list of alphanumeric characters separated by single commas. The list can't start with the , but can end with a ,


Length of the characters will be from 1 to 9. So, considering following examples and their outcomes:



I have written the following regular expression:



Here, it is working fine for all the cases EXCEPT ONE i.e. it always expects the , in the end of the string. But, as per my requirement the string can end with a , or may not end with a , as well. I tried putting ,? but then it starts accepting more than 9 characters since it accepts 0 or 1 , between two entries.

Please suggest how to resolve this issue. Thanks in advance.

Thanks,
Vaibhav Garg
 
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Do you have to use a regular expression for the whole thing? It would be easier to write if (s.charAt(0) != ',' && s.matches(yourRegex) rather than complicating the regular expression.
 
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You just need to replace the ',' in the regular expression so that it accepts as terminator a comma OR end of line ie '(,|$)' .
 
Vaibhav G Garg
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I am able to write down the regular expression for this:


Thanks all for your inputs.
 
Richard Tookey
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That is much more complicated than the approach I suggested!
 
Vaibhav G Garg
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Yes, I agree Richard Tookey. Your approach is much more simpler. Thanks a lot for your inputs.
 
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