Question

i need a regular expression to match only the word’s that match the following conditions. I am using it in my C# program

1. Can be any case
2. Should not have any numbers
3. may contain – and ‘ characters, but are optional
4. Should start with a letter

I have tried using the expression ^([a-zA-Z][\'\-]?)+$ but it doesn’t work.

Here are list of few words that are acceptable

1. London (Case insensitive)
2. Jackson’s
3. non-profit

Here are a list of few words that are not acceptable

1. 12london (contains a number and is not started by a alphabet)
2. -to (does not start with a alphabet)
3. to: (contains : character, any special character other that – and ‘ is not allowed)

Answer 1

^[a-zA-Z][-'a-zA-Z]*$

This matches any word that starts with an alphabetical character, followed by any number of alphabetical characters, – or ‘.

Note that you don’t need to escape the – and ‘ when it’s inside the character [] class, as long as the dash is either the first or last character in the sequence.

Note also that I’ve removed the round brackets from your example – if you don’t want to capture the input, you’ll get better performance by leaving them out.