Get count based on value bash - json

Question

I have data in this format in a file:
{"field1":249449,"field2":116895,"field3":1,"field4":"apple","field5":42,"field6":"2019-07-01T00:00:10","metadata":"","frontend":""}
{"field1":249448,"field2":116895,"field3":1,"field4":"apple","field5":42,"field6":"2019-07-01T00:00:10","metadata":"","frontend":""}
{"field1":249447,"field2":116895,"field3":1,"field4":"apple","field5":42,"field6":"2019-07-01T00:00:10","metadata":"","frontend":""}
{"field1":249443,"field2":116895,"field3":1,"field4":"apple","field5":42,"field6":"2019-07-01T00:00:10","metadata":"","frontend":""}
{"field1":249449,"field2":116895,"field3":1,"field4":"apple","field5":42,"field6":"2019-07-01T00:00:10","metadata":"","frontend":""}
Here, each entry represents a row. I want to have a count of the rows with respect to the value in field one, like:
249449 : 2
249448 : 1
249447 : 1
249443 : 1
How can I get that?

Answer 1

with awk
$ awk -F'[,:]' -v OFS=' : ' '{a[$2]++} END{for(k in a) print k, a[k]}' file

Answer 2

You can use the jq command line tool to interpret JSON data. uniq -c counts the number of occurences.
% jq .field1 < $INPUTFILE | sort | uniq -c
1 249443
1 249447
1 249448
2 249449
(tested with jq 1.5-1-a5b5cbe on linux xubuntu 18.04 with zsh)

Answer 3

Here's an efficient jq-only solution:
reduce inputs.field1 as $x ({}; .[$x|tostring] += 1)
| to_entries[]
| "\(.key) : \(.value)"
Invocation: jq -nrf program.jq input.json
(Note in particular the -n option.)
Of course if an object-representation of the counts is satisfactory, then
one could simply write:
jq -n 'reduce inputs.field1 as $x ({}; .[$x|tostring] += 1)' input.json

Answer 4

Using datamash and some shell utils, change the non-data delimiters to squeezed tabs, count field 3, (it'd be field 2, but there's a leading tab), reverse, then pretty print as per OP spec:
tr -s '{":,}' '\t' < file | datamash -sg 3 count 3 | tac | xargs printf '%s : %s\n'
Output:
249449 : 2
249448 : 1
249447 : 1
249443 : 1