gbMin.js

  1. import { keys, reduce, min, curry } from "ramda"
  3. /**
  4.  * Calculate min for grouped objects.
  5.  *
  6.  * Use it on groupBy objects - the output of Z.groupBy() - to analyze groups.
  7.  *
  8.  * @func
  9.  * @memberOf Z
  10.  * @category Analysis
  11.  * @param {String} col Column within the groups to be analyzed
  12.  * @param {Object} groupByObj Object grouped by a column
  13.  * @return {df} Dataframe with the calculated statistics
  14.  * @see Z.groupBy, Z.gbStd, Z.gbMax, Z.gbCount, Z.gbSum, Z.gbMean, Z.gbDescribe
  15.  * @example
  16.  *
  17.  * const df = [{"label": "A", "value": 7}, {"label": "A", "value": 3}, {"label": "B", "value": 2},  {"label": "B", "value": 5}, {"label": "C", "value": 75}]
  18.  * Z.gbMin("value", Z.groupBy(d => d.label, df))
  19.  * // [{"group": "A", "min": 3}, {"group": "B", "min": 2}, {"group": "C", "min": 75}]
  20.  */
  21. const gbMin = curry((col, groupByObj) => {
  22.   const groups = keys(groupByObj)
  23.   const result = groups.map(g => ({
  24.     group: g,
  25.     min: reduce((acc, value) => min(acc, value[col]), Infinity, groupByObj[g]),
  26.   }))
  27.   return result
  28. })
  30. export default gbMin