newbie question about regular expressions

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Hi
I've tried to understand how to write a regex that will match for me a pattern with the following characteristics:

1. specific characters - I'm guessing the use of square braces "[]"
2. only one of them (not combination or all) - I'm guessing the use of OR "|"
3. zero or one for the selected character - I'm guessing the use of question mark "?"

I don't know how to combine these in order to get what I want
I tried something like this but it doesn't work
"[c?|b?]"

Any help will be great.
Thanks

p.s.
good results will be:
"b","c",""
bad result:
everything else

Posted 16-Jun-13 5:34am

Shahare

Updated 16-Jun-13 5:37am

v2

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2 solutions

Solution 2

C#

public static bool IsAlphabet(string strToCheck)
{
    Regex rg = new Regex("^[a-zA-Z ]*$/;");
    return rg.IsMatch(strToCheck);
}

Posted 16-Jun-13 6:22am

Balimusi

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Shahare 16-Jun-13 12:29pm

Thanks - I'll check this later tonight

Balimusi 16-Jun-13 22:24pm

No problem - hope that helps!

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Thomas Daniels · Accepted Answer · 2013-06-16T05:42:00

Solution 1

Hi,

In a character class (between [ and ] ), only - (the dash) is a special character; ? and | would be treated as 'normal' characters.
Try this:

RegEx

^(c|b)?$

Explanation about the ^ and $ sign:
the ^ sign mentions the start of the string and the $ mentions the end of the string.

Hope this helps.

Posted 16-Jun-13 5:42am

Thomas Daniels

Updated 16-Jun-13 5:55am

v3

Comments

Shahare 16-Jun-13 11:44am

Sorry - checked it and it doesn't do the job - Thanks

Thomas Daniels 16-Jun-13 11:55am

I updated my answer.

Shahare 16-Jun-13 14:57pm

Thank you so much - this is what was missing exactly. And mostly thank you for the clear explanation.

Thomas Daniels 18-Jun-13 11:50am

You're welcome!

Shahare 16-Jun-13 12:29pm

Thanks - I'll check this later tonight