getFloat (Function)
Function retrieves the float value specified in the given path of the JSON element.
Syntax
<FLOAT> json:getFloat(<STRING|OBJECT> json, <STRING> path)
Query Parameters
| Name | Description | Default Value | Possible Data Types | Optional | Dynamic |
|---|---|---|---|---|---|
| json | The JSON input containing float value. | STRING OBJECT | No | Yes | |
| path | The JSON path to fetch the float value. | STRING | No | Yes |
Example 1
@info(name = 'query1')
json:getFloat(json,'$.salary')
The json:getFloat(json,'$.salary') function is designed to extract a floating-point number (a float) from the json object at the path $.salary. If a matching float value is present, it returns that value. For example, given a JSON object such as {'name' : 'John', 'salary' : 12000.0}, it would return 12000.0.
Example 2
@info(name = 'query1')
json:getFloat(json,'$.salary')
The json:getFloat(json,'$.salary') function tries to locate a float value in the json object at the path $.salary. If there is no value at this location, or if the value isn't a float, the function returns null. For instance, with a JSON object like {'name' : 'John', 'age' : 23}, the function returns null because there is no salary key in the JSON object.
Example 3
@info(name = 'query1')
json:getFloat(json,'$.name')
The json:getFloat(json,'$.name') function is designed to find a float value in the json object at the path $.name. If the value at $.name isn't a float, or if no value is present, the function returns null. For example, given a JSON object such as {'name' : 'John', 'age' : 23}, the function returns null because the value at $.name is a string, not a float.
Example 4
CREATE STREAM InputStream (json string);
CREATE SINK STREAM AverageIncomeStream (country string, averageIncome float);
@info(name = 'AverageIncome')
INSERT INTO AverageIncomeStream
SELECT json:getString(json, '$.country') AS country, json:getFloat(json, '$.averageIncome') AS averageIncome
FROM InputStream WINDOW TUMBLING_LENGTH(100);
In this example, an InputStream is created to receive JSON strings, each representing country income details. The AverageIncomeStream is created to output the extracted country name and average income data.
The AverageIncome query listens for events on InputStream. For each batch of 100 events, the query uses json:getString(json, '$.country') and json:getFloat(json, '$.averageIncome') to extract the country (as a string) and average income (as a float) from each JSON string. These extracted values are then inserted into the AverageIncomeStream.