Regular expression to allow 1 digit at beginning of 5 letter group

Question

I currently have this regular expression:

/(^| )[az]{5}-[az]{5}( |$)/i

start of string or space, 5 letters, literal dash, 5 letters, space or end of string, case insensitive.

This finds a string that looks like this: pejnd-zxdgn

I need to allow the first letter only to be a digit instead of a letter.

How do I write this?

Edit: To clarify

should match: pejnd-zxdgn or 7ejnd-zxdgn

Should not match 7pejnd-zxdgn or 7ejn-zxdgn or p7ejnd-zxdgn

Answer 1

Just add a pattern for digit before the [az] part. And change the quantifier to {4} :

/(^| )[0-9][a-z]{4}-[0-9][a-z]{4}( |$)/i

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After your update, you just want the first character to be digit or character. Also, you can use word boundaries - \\b at the beginning and the end, as noted in comments. So, change your regex to:

/\b[a-z0-9][a-z]{4}-[a-z]{5}\b/i

Answer 2

使用'\\ d'匹配单个数字。