# Mutate add\_field gives sprint f format for nil values. How to solve this?
**URL:** https://discuss.elastic.co/t/mutate-add-field-gives-sprint-f-format-for-nil-values-how-to-solve-this/181473
**Category:** Logstash
**Created:** [May 16, 2019, 7:58pm UTC](https://discuss.elastic.co/t/mutate-add-field-gives-sprint-f-format-for-nil-values-how-to-solve-this/181473 "2019-05-16T19:58:28Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@rkhapre](https://discuss.elastic.co/u/rkhapre)
#### Post date: [May 16, 2019, 7:58pm UTC](https://discuss.elastic.co/t/mutate-add-field-gives-sprint-f-format-for-nil-values-how-to-solve-this/181473/1 "2019-05-16T19:58:28Z")
Hi All
I am using mutate add\_field in my confile
```
mutate {
add_field => {"CloserName" => "%{[Bugs]CloserName}"}
}
```
The value for many CloserName is null but some has value
Which ever record is having null values, i am not getting null instead i am getting sprintf
format.
i get the output like this
`%{[Bugs]CloserName}`
I can use If condition to solve for one column, i have 200 columns like this, i cannot write if condition for each of these newly added field.
I think this will be common problem, please let me know if someone is having solution for this?
---
### Author:  [@Badger](https://discuss.elastic.co/u/Badger)
#### Post date: [May 16, 2019, 8:01pm UTC](https://discuss.elastic.co/t/mutate-add-field-gives-sprint-f-format-for-nil-values-how-to-solve-this/181473/2 "2019-05-16T20:01:58Z")
That is not a valid sprintf reference. Is CloserName and field within the [Bugs] object? If so, use
```
%{[Bugs][CloserName]}
```
If it still does not work, configure
```
output { stdout { codec => rubydebug } }
```
and show us what an event looks like.
---
### Author:  [@rkhapre](https://discuss.elastic.co/u/rkhapre)
#### Post date: [May 16, 2019, 8:09pm UTC](https://discuss.elastic.co/t/mutate-add-field-gives-sprint-f-format-for-nil-values-how-to-solve-this/181473/3 "2019-05-16T20:09:41Z")
Hi @Badger
I tried your suggested sprintf, still i get the same value. Pasting the json from kibana
> {
> "\_index": "sdfdsfff",
> "\_type": "logs",
> "\_id": "AWrCP3j9UCagDdWuJhQ7",
> "\_score": 1,
> "\_source": {
> "BugTypeName": "Support",
> "Status": "Under Review",
> "Severity": "Normal",
> "CloserName": "%{[Bugs][CloserName]}",
> "@timestamp": "2019-05-16T20:05:04.413Z",
> "DaysOpened": "6",
> "BugNumber": "1010",
> "@version": "1",
> "DateModified": "5/10/2019 3:19 AM"
> },
> "fields": {
> "@timestamp": [
> 1558037104413
> ]
> }
> }
This is what i am using in conf file
` add_field => {"CloserName" => "%{[Bugs][CloserName]}"}`
Under Bugs, this is how my value looks like, i am just parsing it to new field
> [
> {
> .............
> .
> .
>
> ```
> "CloserName": null,
> "DaysOpened": "8",
> "ReportedVersionID": null,
> "BugsSeverityID": "38522",
> .
> .
> .
> },
>
> {
>
> }
>
> ```
>
> ]
---
### Author:  [@Badger](https://discuss.elastic.co/u/Badger)
#### Post date: [May 16, 2019, 8:38pm UTC](https://discuss.elastic.co/t/mutate-add-field-gives-sprint-f-format-for-nil-values-how-to-solve-this/181473/4 "2019-05-16T20:38:13Z")
OK, so that event does not have a [Bugs][CloserName] field, so you should expect the mutate to leave it with the sprintf reference. You could use something like [this](https://discuss.elastic.co/t/removing-fields-with-certain-value-or-if-mapping-is-not-found-from-the-output/180941/2) to remove any fields whose value starts with "%{".
---
### Author:  [@rkhapre](https://discuss.elastic.co/u/rkhapre)
#### Post date: [May 18, 2019, 1:01pm UTC](https://discuss.elastic.co/t/mutate-add-field-gives-sprint-f-format-for-nil-values-how-to-solve-this/181473/5 "2019-05-18T13:01:58Z")
Thanks @Badger, from the linked topic, i got my solution
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [June 15, 2019, 1:02pm UTC](https://discuss.elastic.co/t/mutate-add-field-gives-sprint-f-format-for-nil-values-how-to-solve-this/181473/6 "2019-06-15T13:02:10Z")
This topic was automatically closed 28 days after the last reply. New replies are no longer allowed.