Using Jolt in Big Data Streams to Remove Nulls
Using Jolt in Big Data Streams to Remove Nulls
Learn how to use Jolt code within your big data streams to remove null values with some example source data and JSON code.
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In this article, we're going to learn about using Jolt code in your big data streams to remove null values.
Here's some JSON code for using Jolt in big data streams:
[
{
"operation": "default",
"spec": {
"address": "",
"somesensorvalues[]": {
"*": {
"sensor1": false
}
},
"startTime": "",
"onStartTime": "",
"markId": "",
"markName": "",
"stoppedTime": "",
"startTime2": "",
"powerSetting": "false",
"speed": 0,
"id": 0,
"city": "",
"state": ""
}
},
{
"operation": "shift",
"spec": {
"*": "&"
}
}
]To help you understand, here's some example source data:
{
"address" : "2000 Electric Avenue",
"somesensordata" : [ {
"sensor1" : null
} ],
"city" : "hightstown",
"deviceId" : 5454545,
"dateTime" : "2017-08-07 14:56:09",
"id" : 6831491,
"idle" : false,
"startTime" : null,
"onStartTime" : null,
"markId" : null,
"markName" : null,
"zipCode" : "08520"
}
Yeah, sometimes you really don't want to see any nulls!
The above Jolt script will copy all the values in a source JSON document to a destination. For the explicitly named variables like speed, it will replace nulls with the value on the right. So for speed, it will put in a 0 to represent a null value.
For embedded lists of values (likesensor1 inside of somesensorvalues array), the syntax is a bit different.
References
Hortonworks Sandbox for HDP and HDF is your chance to get started on learning, developing, testing and trying out new features. Each download comes preconfigured with interactive tutorials, sample data and developments from the Apache community.
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