How to create a new field?

[metylkinandrey]

Tell me, what should I do in my case, I need from the field: 1.SAPS-SIS.TO.LSP.SEND, or: "12.SAPS-SIS.TO.LSP.RECEIVE
Get field: "routepointIDnum": "1" or "routepointIDnum": "12"

I tried like this and it almost works:
index="main" sourcetype="testsystem-script333"
| eval routepointID_num=substr(routepointID,1,2)
| table routepointID_num

Almost because I get:
"routepointIDnum": "1." or "routepointIDnum": "12"
And I need:
"routepointIDnum": "1" or "routepointIDnum": "12"

[ITWhisperer]

index="main" sourcetype="testsystem-script333"
| rex field=routepointID "^(?<routepointID_num>\d+)\."
| table routepointID_num

[metylkinandrey]

Excellent thank you!