How to filter an array of objects based on values in an inner array with jq?
ArraysJsonSelectJqNegationArrays Problem Overview
Given this input:
[ { "Id": "cb94e7a42732b598ad18a8f27454a886c1aa8bbba6167646d8f064cd86191e2b", "Names": [ "condescending_jones", "loving_hoover" ]
},
{
"Id": "186db739b7509eb0114a09e14bcd16bf637019860d23c4fc20e98cbe068b55aa",
"Names": [
"foo_data"
]
},
{
"Id": "a4b7e6f5752d8dcb906a5901f7ab82e403b9dff4eaaeebea767a04bac4aada19",
"Names": [
"jovial_wozniak"
]
},
{
"Id": "76b71c496556912012c20dc3cbd37a54a1f05bffad3d5e92466900a003fbb623",
"Names": [
"bar_data"
]
}
]
I'm trying to construct a filter with jq that returns all objects with Id
s that do not contain "data" in the inner Names
array, with the output being newline-separated. For the above data, the output I'd like is:
cb94e7a42732b598ad18a8f27454a886c1aa8bbba6167646d8f064cd86191e2b
a4b7e6f5752d8dcb906a5901f7ab82e403b9dff4eaaeebea767a04bac4aada19
I think I'm somewhat close with this:
(. - select(.Names[] contains("data"))) | .[] .Id
but the select
filter is not correct and it doesn't compile (get error: syntax error, unexpected IDENT
).
Arrays Solutions
Solution 1 - Arrays
Very close! In your select
expression, you have to use a pipe (|
) before contains
.
This filter produces the expected output.
. - map(select(.Names[] | contains ("data"))) | .[] .Id
The jq Cookbook has an example of the syntax.
> # Filter objects based on the contents of a key > > E.g., I only want objects whose genre key contains "house". > > $ json='[{"genre":"deep house"}, {"genre": "progressive house"}, {"genre": "dubstep"}]' > $ echo "$json" | jq -c '.[] | select(.genre | contains("house"))' > {"genre":"deep house"} > {"genre":"progressive house"}
Colin D asks how to preserve the JSON structure of the array, so that the final output is a single JSON array rather than a stream of JSON objects.
The simplest way is to wrap the whole expression in an array constructor:
$ echo "$json" | jq -c '[ .[] | select( .genre | contains("house")) ]'
[{"genre":"deep house"},{"genre":"progressive house"}]
You can also use the map function:
$ echo "$json" | jq -c 'map(select(.genre | contains("house")))'
[{"genre":"deep house"},{"genre":"progressive house"}]
map unpacks the input array, applies the filter to every element, and creates a new array. In other words, map(f)
is equivalent to [.[]|f]
.
Solution 2 - Arrays
Here is another solution which uses any/2
map(select(any(.Names[]; contains("data"))|not)|.Id)[]
with the sample data and the -r
option it produces:
cb94e7a42732b598ad18a8f27454a886c1aa8bbba6167646d8f064cd86191e2b
a4b7e6f5752d8dcb906a5901f7ab82e403b9dff4eaaeebea767a04bac4aada19