md`# Grouping data Oct. 3`
d3 = require("d3")
// import basbeall player salary information
raw = d3.tsv("https://gist.githubusercontent.com/lathropd/0d63302f6c3c1014f2cd3846a23967a8/raw/9e7f666b7a2a83fb6d8e444215d7c46a0d60a62b/baseball.tsv")
formatted = d3.nest()
.key( d => d.POS )
.rollup( values => values.length )
.entries(raw)
.map( d => {
return {
position: d.key,
"number of players": d.value
}
})
import {table} from "@tmcw/tables"
table(formatted)
// this is a function that receives a list of players and returns a summary of them
function summarize(players) {
let count = players.length
let pay = players.map( d => +d["Average Pay"] )
let mean = d3.mean(pay)
return {count, mean}
}
summarize(raw)
maurice = d3.nest()
.key( d => d.POS )
.rollup( summarize )
.entries(raw)
.map( d => {
return {
position: d.key,
"number of players": d.value.count,
"average annual pay": d.value.mean
}
})
table(maurice)
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