How to include a multiline text in regex pattern

I have a pattern ^[0-9]+$, but I want it to include a \n new-line symbol so that the string like below would be valid:
123\n345\n678\n9752\n or in other words:

123
345
678
9752

>Solution :

Assuming you don’t want to include leading/trailing newlines, try:

\A[0-9]+(?:\n[0-9]+)*\Z

See an online demo.

• \A – Start-string anchor;
• [0-9]+ – 1+ digits;
• (?:\n[0-9]+)* – Match nested non-capture group 0+ times validating a single newline character and 1+ digits;
• \Z – End-string anchor.

Note: As per my comments, ^[0-9]+(?:\n[0-9]+)*$ would also work with the right flags turned on/off.