Question

I’m trying to make a case insensitive regular expression for my shipping section that catches all postcodes which start with GY1 – GY9 (single figures only). So far, it catches all gy postcodes, not just 1-9. Here is what I have so far:

^[gG][yY][1-9]{1}

Any ideas?

Edit:

I used the following regex based on stema’s answer below:

^[gG][yY][1-9]\s?[1-9][a-zA-Z]{2}$

Answer 1

Try this

/^GY[1-9](?!\d)/i

Your regex matches because there can be anything following your digit.

• I use the negative lookahead assertion (?!\d) to ensure that there is not a digit after your [1-9].

• The flag i at the end makes the regex matching case insensitive, so no need for [gG][yY]

See it here on Regexr

Edit:

When the second part can has only 1 leading digit you can try this

^GY[1-9]\s?[1-9][a-z]{2}

See it here on Regexr

Means starts with “GY” then a digit from 1-9, followed by an optional space, then another digit and two letters.