Parsing float value from string by jq

Question

I have a particular JSON data which contain float value that I need to conditionally process over an array of JSON. This is an example of one JSON instance:

[
   {
      "a": "0",
      "b": "66.67",
      "c": "0",
      "d": "0"
   },
   {
      "a": "12.33",
      "b": "0",
      "c": "60.2",
      "d": "19.3"
   },
   {
      "a": "70.0",
      "b": "92.67",
      "c": "0",
      "d": "0"
   }
]

and I wish to conditionally select like

cat mydata.json | jq '.[] | select((.a > 50) and (.b > 50))'

and it should sound like

{
      "a": "70.0",
      "b": "92.67",
      "c": "0",
      "d": "0"
}

The problem is my original data is a string value and I have no idea how to parse it for a conditional selection.

Answer 1

Simply with jq's tonumber function:

jq '.[] | select((.a|tonumber) > 50 and (.b|tonumber) > 50)' mydata.json

The output:

{
  "a": "70.0",
  "b": "92.67",
  "c": "0",
  "d": "0"
}