digits = d3.range(10)
numbers = d3.cross(digits, digits, digits, digits)
hi = number => number.slice().sort((a, b) => b - a)
hi([2, 1, 3, 4])
lo = number => number.slice().sort((a, b) => a - b)
lo([2, 1, 3, 4])
value = number =>
((+number[0] * 10 + +number[1]) * 10 + +number[2]) * 10 + +number[3]
value([2, 1, 3, 4])
step = number =>
(value(hi(number)) - value(lo(number)) + 10000)
.toString()
.slice(1)
.split("")
.map(d => +d)
step([2, 1, 3, 4])
seq = number => {
let n,
seq = [];
do {
seq.push(number);
n = number;
number = step(n);
} while (n.join("") !== number.join(""));
return seq;
}
seq([2, 1, 3, 4])
count = number => seq(number).length - 1
count([2, 1, 3, 4])
d3 = require("d3@5", "d3-selection@2.0.0-rc.2", "d3-array@2")
import { checkbox } from "@jashkenas/inputs"
Purpose-built for displays of data
Observable is your go-to platform for exploring data and creating expressive data visualizations. Use reactive JavaScript notebooks for prototyping and a collaborative canvas for visual data exploration and dashboard creation.
