Regex to allow groups of 7 numbers and spaces

Question

I'm looking for help with a regex.

My input field should allow only groups of up to 7 digits, and an unlimited number spaces whether at the beginning, middle, or end.

Here are a few examples of valid matches

Match1:
478 2635478     14587   9652

Match2 (spaces at the end):
   14     2  55586

I tried this regex

^( )*[0-9]{1,7}(( )*[0-9]{1-7})*( )*$

It matches when the group is 8 digits.

anubhava · Answer

Converting my comment to answer so that solution is easy to find for future visitors.

You may use this regex:

^ *[0-9]{1,7}(?: +[0-9]{1,7})* *$

RegEx Breakup:

^: Start
*: Match 0 or more spaces
[0-9]{1,7}: Match 1 to 7 digits -(?: +[0-9]{1,7})*: Match 1+ spaces followed by a match of 1 to 7 digits. Repeat this group 0 or more times
*: Match 0 or more spaces
$: End

bobble bubble · Answer

An idea with one group and use of a word boundary to separate blocks:

^ *(?:\d{1,7}\b *)+$

\b will require a space or the end after each \d{1,7} repetition.