I have deep nested jsons and I want to count how many keys I have in front of a scalar with jq. Here a very simplified example
{
"one": {
"two": {
"three": [
{
"four": [
{
"five": [
{
"six": [
{
"sevenA": {
"eightA": [
{
"nineA": "Blub"
},
{
"nineB": "def"
},
{
"nineC": "foo"
},
{
"nineD": 22
}
]
}
},
{
"sevenB": {
"eightB": [
{
"nineE": "Bla"
},
{
"nineF": "int"
},
{
"nineG": "s"
},
{
"nineH": 60
}
]
}
}
]
}
]
}
]
}
]
}
}
}
With the following command I am able to count keys and arrays in front of the scalar.
jq '[paths(scalars)] | map(length)'
[
14,
14,
14,
14,
14,
14,
14,
14
]
like this
"one.two.three.[].four.[].five.[].six.[].sevenA.eightA.[].nineA",
"one.two.three.[].four.[].five.[].six.[].sevenA.eightA.[].nineB",
"one.two.three.[].four.[].five.[].six.[].sevenA.eightA.[].nineC",
"one.two.three.[].four.[].five.[].six.[].sevenA.eightA.[].nineD",
"one.two.three.[].four.[].five.[].six.[].sevenB.eightB.[].nineE",
"one.two.three.[].four.[].five.[].six.[].sevenB.eightB.[].nineF",
"one.two.three.[].four.[].five.[].six.[].sevenB.eightB.[].nineG",
"one.two.three.[].four.[].five.[].six.[].sevenB.eightB.[].nineH"
So I get as result 14 for my example above.
But I would like to count only the keys like this.
".one.two.three[].four[].five[].six[].sevenB.eightB[].nineE"
".one.two.three[].four[].five[].six[].sevenB.eightB[].nineF"
".one.two.three[].four[].five[].six[].sevenB.eightB[].nineG"
".one.two.three[].four[].five[].six[].sevenB.eightB[].nineH"
".one.two.three[].four[].five[].six[].sevenB.eightB[].nineE"
".one.two.three[].four[].five[].six[].sevenB.eightB[].nineF"
".one.two.three[].four[].five[].six[].sevenB.eightB[].nineG"
".one.two.three[].four[].five[].six[].sevenB.eightB[].nineH"
that I count 9 keys in front of the scalar or 8 keys in front of the key value pair for the scalar.
Could somebody maybe help me how I could do this with jq?
To produce a stream of key-depths, you could write:
jq 'paths(scalars) | map(strings) | length' input.json
Or with an eye on potential efficiency enhancements, you could use the generic stream-oriented count/1:
def count(stream):
reduce stream as $_ (0; .+1);
paths(scalars) | count(.[] | strings)
Or to compute the maximum key depth using a generic stream-oriented "max" function:
def count(stream):
reduce stream as $_ (0; .+1);
# max(empty) is empty
def max(stream):
reduce (stream | [.]) as $x (null;
if . == null or $x > . then $x else . end )
| if . == null then empty else .[0] end;
max(paths(scalars) | count(.[] | strings))