by.md

jline-by

Reduce values to some breakdown. E.g. if you have a whole lot of records that look like this:

{"state":"Georgia", "year":1982, "sightings":27, "validatedSightings":19}

You may want to get the total number of sightings by year. You can do this with:

cat data | jline-by year -- sightings

This will output one JSON line for each year together with the total number of sightings for that year:

{"sightings":135,"year":"1982"}
{"sightings":172,"year":"1983"}
{"sightings":211,"year":"1984"}

Command line:

The general form is:

cat data | jline-by <breakdown> ... -- <value> ...

You may rename a breakdown or value using colon notation: old.path:new

cat data | jline-by state year -- sightings
cat data | jline-by year:Y -- sightings validatedSightings
cat data | jline-by year:Y -- sightings validatedSightings:validated