Splunk Search

## How to create a new field from existing field values

Path Finder

I have a field with values similar to this: TagName=15PI008_15

The _15 portion of this value is the part I need to extract into a new field called "WellNumber". However, I need to transform this value into something else that makes more sense to the user e.g.

_15 = H315
_3 = H305
_19 = H319

etc.

How can I do this in search and is there a way of doing this by default?

Tags (1)
1 Solution
SplunkTrust

Hi stevenbutterworth,
you can move in two ways depending by the number of values you have, in other words, you have anyway to extract the WellNumber using rex command

``````| rex field=your_field "_(?<WellNumber>\d+)"
``````

then if you have few different values, you can use eval command

``````| eval New_field=case(WellNumber="15","H315",WellNumber="3","H305",WellNumber="19","H319")
``````

if instead you have many different values, you can build a lookup containing the correlation values:

``````WellNumber,New_field
15,H315
3,H305
19,H319
``````

and use lookup command

``````| lookup my_lookup.csv WellNumber OUTPUT New_field
``````

Bye.
Giuseppe

SplunkTrust

Hi stevenbutterworth,
you can move in two ways depending by the number of values you have, in other words, you have anyway to extract the WellNumber using rex command

``````| rex field=your_field "_(?<WellNumber>\d+)"
``````

then if you have few different values, you can use eval command

``````| eval New_field=case(WellNumber="15","H315",WellNumber="3","H305",WellNumber="19","H319")
``````

if instead you have many different values, you can build a lookup containing the correlation values:

``````WellNumber,New_field
15,H315
3,H305
19,H319
``````

and use lookup command

``````| lookup my_lookup.csv WellNumber OUTPUT New_field
``````

Bye.
Giuseppe

Path Finder

Thanks Giuseppe

I did have something like this in mind but wasn't sure of the execution method.

It works great now.

Steve

SplunkTrust

To do it in a search, first extract WellNumber using `rex`.

``````... | rex field=TagName "_(?<WellNumber>\d+)" |
``````

Then transform WellNumber using either `case` or `lookup`

``````... | case WellField=case(WellNumber==15,"H315", WellNumber==3, "H305", WellNumber==19, "H319", 1==1, WellNumber) | ...

... | lookup WellNumbers.csv WellNumber OUTPUT WellField | ...
``````

I'd use `case` if the number of options is small and doesn't change often; otherwise, use a lookup.

---
If this reply helps you, Karma would be appreciated.
Explorer
`````` | replace "_*" WITH "H3*" IN WellNumber
``````

I'm not sure it's what u want.
Would you rather do it directly from extraction?

Super Champion

try something like this:

``````|rex field=fieldname "_(?<WellNumber>\d+)"|eval WellNumber="H3".substr("00".WellNumber,-2)
``````
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