import { keys, curry } from "ramda"
/**
* Calculate count for grouped objects.
*
* Use it on groupBy objects - the output of Z.groupBy() - to analyze groups.
*
* @func
* @memberOf Z
* @category Analysis
* @param {String} col Column within the groups to be analyzed
* @param {Object} groupByObj Object grouped by a column
* @return {df} Dataframe with the calculated statistics
* @see Z.groupBy, Z.gbMin, Z.gbMax, Z.gbStd, Z.gbSum, Z.gbMean, Z.gbDescribe
* @example
*
* const df = [{"label": "A", "value": 7}, {"label": "A", "value": 3}, {"label": "B", "value": 2}, {"label": "B", "value": 5}, {"label": "C", "value": 75}]
* Z.gbCount("value", Z.groupBy(d => d.label, df))
* // [{"count": 2, "group": "A"}, {"count": 2, "group": "B"}, {"count": 1, "group": "C"}]
*/
const gbCount = curry((col, groupByObj) => {
const groups = keys(groupByObj)
return groups.map(g => ({ group: g, count: groupByObj[g].length }))
})
export default gbCount