# Converting a string field to an IP field
**URL:** https://discuss.elastic.co/t/converting-a-string-field-to-an-ip-field/78733
**Category:** Elasticsearch
**Created:** [March 15, 2017, 3:26pm UTC](https://discuss.elastic.co/t/converting-a-string-field-to-an-ip-field/78733 "2017-03-15T15:26:24Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@Cylindric](https://discuss.elastic.co/u/Cylindric)
#### Post date: [March 15, 2017, 3:26pm UTC](https://discuss.elastic.co/t/converting-a-string-field-to-an-ip-field/78733/1 "2017-03-15T15:26:24Z")
I have a bunch of log data that contains three IP fields, but these have been shipped as a string.
I have created a new index template that defines these fields as IP now, and new data is coming in nicely, because my app passes in `null` for fields that don't have a valid IP, but if I `_reindex` my existing data, I get errors due to the empty strings that are currently in there.
Is there any way of using _painless_ scripts or something to catch invalid addresses on the way through and replacing them with nulls, instead of just abandoning the reindex?
The closest I could find was something like this:
```
POST _reindex
{
"source": {
"index": "twitter"
},
"dest": {
"index": "new_twitter"
},
"script": {
"inline": "if (ctx._source.ip == '') {ctx._source.ip = null}",
"lang": "painless"
}
}
```
How would I run that snippet on three separate fields?
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [April 12, 2017, 3:26pm UTC](https://discuss.elastic.co/t/converting-a-string-field-to-an-ip-field/78733/2 "2017-04-12T15:26:28Z")
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