Question

I have an example:

var p =  /^(\d)+$/;
var s = '834736';
var a = p.exec(s);
console.log(a);

I want to group the first digit ^(\d), but the result is:

["834736", "6"]

It catch the last digit. Anybody can explain to me? Thanks!

Answer 1

If you want to catch the first digit only, put the first digit in the group, and match the rest of the digits outside of the group, like so:

/^(\d)\d*$/

The reason you only catch the last digit is, that you repeat the same group for each digit you match. This means, every time it matches a new digit, the old contents of the group is replaced, and thus you get the last digit as the result of your group.