# Filter to get only some data from msg.payload: string
**URL:** https://discourse.nodered.org/t/filter-to-get-only-some-data-from-msg-payload-string/28174
**Category:** General
**Created:** [11 June 2020 12:38 UTC](https://discourse.nodered.org/t/filter-to-get-only-some-data-from-msg-payload-string/28174 "2020-06-11T12:38:00Z")
**Posts on this page:** 9
**Page:** 1
### Author:  [@pwgrau](https://discourse.nodered.org/u/pwgrau)
#### Post date: [11 June 2020 12:38 UTC](https://discourse.nodered.org/t/filter-to-get-only-some-data-from-msg-payload-string/28174/1 "2020-06-11T12:38:00Z")
Hello, I have this data via mqtt and I want to take it to an influxdb to graph it in a grafana, the values โโthat arrive in the graph are this whole chain, and I just need to get temperature and humidity data in number:
{"Time":"2020-06-11T13:36:11","SI7021":{"Temperature":15.9,"Humidity":74.5,"DewPoint":11.4},"TempUnit":"C"}
I am a novice in node-red I would appreciate that you explain with what specific nodes I could make these filters.
---
### Author:  [@Colin](https://discourse.nodered.org/u/Colin)
#### Post date: [11 June 2020 12:50 UTC](https://discourse.nodered.org/t/filter-to-get-only-some-data-from-msg-payload-string/28174/2 "2020-06-11T12:50:41Z")
Have a read in the node red docs at the section Working with Messages. That should help a lot.
[Edit] also, if the example you posted is a string then set the MQTT node to output Parsed JSON. It will convert the JSON string to a javascript object which will make it much easier.
---
### Author:  [@mtoko](https://discourse.nodered.org/u/mtoko)
#### Post date: [11 June 2020 12:51 UTC](https://discourse.nodered.org/t/filter-to-get-only-some-data-from-msg-payload-string/28174/3 "2020-06-11T12:51:37Z")
The data is a JSON Object and you can extract the temperature and humidity values using a change node. See the example flow. It is possible that the message from the MQTT node is a JSON string and you will need to add a JSON node to convert the output of the MQTT node to a JSON Object
```auto
[
{
"id": "6ff4951.acf306c",
"type": "tab",
"label": "Flow 7",
"disabled": false,
"info": ""
},
{
"id": "fc5901ca.92592",
"type": "inject",
"z": "6ff4951.acf306c",
"name": "",
"topic": "",
"payload": "{\"Time\":\"2020-06-11T13:36:11\",\"SI7021\":{\"Temperature\":15.9,\"Humidity\":74.5,\"DewPoint\":11.4},\"TempUnit\":\"C\"}",
"payloadType": "json",
"repeat": "",
"crontab": "",
"once": false,
"onceDelay": 0.1,
"x": 410,
"y": 140,
"wires": [
[
"b0ba994e.3fe428",
"1d4f00f9.b6b25f",
"d316e8b9.a21aa8"
]
]
},
{
"id": "b0ba994e.3fe428",
"type": "debug",
"z": "6ff4951.acf306c",
"name": "",
"active": true,
"tosidebar": true,
"console": false,
"tostatus": false,
"complete": "false",
"x": 740,
"y": 160,
"wires": []
},
{
"id": "1d4f00f9.b6b25f",
"type": "change",
"z": "6ff4951.acf306c",
"name": "",
"rules": [
{
"t": "set",
"p": "payload",
"pt": "msg",
"to": "payload.SI7021.Temperature",
"tot": "msg"
}
],
"action": "",
"property": "",
"from": "",
"to": "",
"reg": false,
"x": 660,
"y": 320,
"wires": [
[
"f7bfa24c.9fdeb"
]
]
},
{
"id": "f7bfa24c.9fdeb",
"type": "debug",
"z": "6ff4951.acf306c",
"name": "",
"active": true,
"tosidebar": true,
"console": false,
"tostatus": false,
"complete": "false",
"x": 960,
"y": 340,
"wires": []
},
{
"id": "d316e8b9.a21aa8",
"type": "change",
"z": "6ff4951.acf306c",
"name": "",
"rules": [
{
"t": "set",
"p": "payload",
"pt": "msg",
"to": "payload.SI7021.Humidity",
"tot": "msg"
}
],
"action": "",
"property": "",
"from": "",
"to": "",
"reg": false,
"x": 680,
"y": 400,
"wires": [
[
"2bf5fc11.4dba04"
]
]
},
{
"id": "2bf5fc11.4dba04",
"type": "debug",
"z": "6ff4951.acf306c",
"name": "",
"active": true,
"tosidebar": true,
"console": false,
"tostatus": false,
"complete": "false",
"x": 920,
"y": 400,
"wires": []
}
]
```
---
### Author:  [@Colin](https://discourse.nodered.org/u/Colin)
#### Post date: [11 June 2020 12:54 UTC](https://discourse.nodered.org/t/filter-to-get-only-some-data-from-msg-payload-string/28174/4 "2020-06-11T12:54:28Z")
> [@mtoko](#):
>
> you will need to add a JSON node
The MQTT node has this capability built in, just tell it to parse the JSON string and convert it to a javascript object (note, a javascript object, it is not correct to call it a JSON object, JSON is always a string).
---
### Author:  [@mtoko](https://discourse.nodered.org/u/mtoko)
#### Post date: [11 June 2020 13:06 UTC](https://discourse.nodered.org/t/filter-to-get-only-some-data-from-msg-payload-string/28174/5 "2020-06-11T13:06:27Z")
Thanks Colin, always learning! ๐
---
### Author:  [@pwgrau](https://discourse.nodered.org/u/pwgrau)
#### Post date: [11 June 2020 13:08 UTC](https://discourse.nodered.org/t/filter-to-get-only-some-data-from-msg-payload-string/28174/6 "2020-06-11T13:08:59Z")
I passed it to json I have it as an object and I could remove some data with the change node, I think I have to improve the filter so as not to display and have the pure data I need such as temperature and humidity
---
### Author:  [@mtoko](https://discourse.nodered.org/u/mtoko)
#### Post date: [11 June 2020 13:52 UTC](https://discourse.nodered.org/t/filter-to-get-only-some-data-from-msg-payload-string/28174/7 "2020-06-11T13:52:20Z")
---
### Author:  [@pwgrau](https://discourse.nodered.org/u/pwgrau)
#### Post date: [11 June 2020 15:10 UTC](https://discourse.nodered.org/t/filter-to-get-only-some-data-from-msg-payload-string/28174/8 "2020-06-11T15:10:27Z")
Thank you all very much, it worked that way
---
### Author:  [@system](https://discourse.nodered.org/u/system)
#### Post date: [25 June 2020 15:10 UTC](https://discourse.nodered.org/t/filter-to-get-only-some-data-from-msg-payload-string/28174/9 "2020-06-25T15:10:27Z")
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