Public
Edited
Jun 25, 2023
penguinData
Type Table, then Shift-Enter. Ctrl-space for more options.
// Add your code here to do the wrangling steps above!
penguinData
.map((d) => ({
species: d.species,
massKilograms: d.body_mass_g / 1000,
billRatio: d.culmen_length_mm / d.culmen_depth_mm
}))
.filter((d) => d.billRatio > 3.5)
// Find the range of culmen lengths in penguinData:
d3.extent(penguinData, d => d.culmen_length_mm)
// Mean of all body mass. (grams) values in penguinData:
d3.mean(penguinData, d => d.body_mass_g)
// Alternatively:
d3.mean(penguinData.map(d => d.body_mass_g))
// Standard deviation of culmen depth:
d3.deviation(penguinData, d => d.culmen_depth_mm)
d3
.nest()
.key((d) => d.island)
.entries(penguinData)
.map((d) => d.key)
penguinData.map((penguins) => penguins.island)
penguinData
Type Table, then Shift-Enter. Ctrl-space for more options.
// Group penguinData by species (store Map as groupSpecies):
groupSpecies = d3.group(penguinData, (d) => d.species)
// Then get just the Adelies:
groupSpecies.get("Adelie")
// Group penguinData by species and island (store as groupSpeciesIsland):
groupSpeciesIsland = d3.group(
penguinData,
(d) => d.species,
(d) => d.island
)
// Get observations for Adelie penguins on Dream Island:
groupSpeciesIsland.get("Adelie").get("Dreamg")
// Find the mean body mass by penguin species:
d3.rollup(
penguinData,
(v) => d3.mean(v, (d) => d.body_mass_g),
(d) => d.species
)
// Find the mean flipper length by penguin species and sex:
d3.rollup(
penguinData,
(v) => d3.mean(v, (d) => d.flipper_length_mm),
(d) => d.species,
(d) => d.sex
)
arrayOfArrays = [
[1, 2],
[3, 4]
]
arrayOfArrays.map(([firstNumber, secondNumber]) => ({
firstNumber,
secondNumber
}))
// Use flatRollup to find mean body mass by penguin species, then map to get an array of objects:
// this is a way to turn an array of arrays into an array of objects
d3
.flatRollup( // this function will retun an array of arrays
penguinData, // take the original dataset
(v) => d3.mean(v, (d) => d.body_mass_g), // calculate the mean. v stands for value
(d) => d.species // we want to group by species
)
// transform array of arrays into array of objects using specified parameters
.map(([species, meanMass]) => ({ species, meanMass }))
// Create a new bar chart with Observable Plot to visualize mean body mass by species:
Plot.plot({
marks: [
Plot.barY(
penguinData,
Plot.groupX(
{ y: "mean" },
{ y: "body_mass_g", x: "species", sort: { x: "y", reverse: true } }
)
)
]
})
import { showMe } from "@observablehq/show-me"
d3 = import("https://cdn.skypack.dev/d3@7")
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.
