function parse_file(text, start, end = undefined, columns) {
const data = text.split("\n").slice(start, end);
return data.map((d) => {
const values = d
.split(" ")
.filter((value) => value !== "")
.slice(0, columns.length + 1);
const row = {};
columns.forEach((c, i) => (row[c] = +values[i]));
return row;
});
}