Notebooks 2.0 is here.
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Edited
Apr 26, 2023
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// Add your code here to do the wrangling steps above!
penguinData.map(d => ({speices: d.species,
massKilograms: d.body_mass_g / 1000,
billRatio: d.culmen_length_mm / d.culmen_depth_mm}))
.filter(d => d.billRation > 3.5) // iterates over each object, d, returning a new object with the following keys
// Find the minimum culmen length in penguinData:
d3.min(penguinData, d => d.culmen_length_mm)
// Find the range of culmen lengths in penguinData: d3.min(penguinData, d => d.culmen_length_mm)
d3.extent(penguinData, d => d.culmen_length_mm) // note its not "range"
// 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)) // you can provide an array of values as well, using this syntax
// Standard deviation of culmen depth:
d3.deviation(penguinData, (d) => d.culmen_depth_mm)
// Count of flipper length values:
d3.count(penguinData, d => d.flipper_length_mm)
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) // this creates a map with 3 key value pairs: species is the key and value is how many objects are in it
// Then get just the Adelies:
groupSpecies.get("Adelie") // only need to give it the key, returns array
// 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("Dream") // get an array of objects on dream island. really cool way to create subsets
// Find the mean body mass by penguin species:
d3.rollup(penguinData, v => d3.mean(v, d => d.body_mass_g), d => d.species) // the last part of this is the species
// Find the mean flipper length by penguin species and sex:
d3.rollup(penguinData, v => d3.mean(v, d => d.body_mass_g),
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:
d3
.flatRollup(
penguinData,
(v) => d3.mean(v, (d) => d.body_mass_g),
(d) => d.species
)
.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" }, // you can change this to any summary statistic
{ y: "body_mass_g", x: "species", sort: { x: "y", reverse: true } }
)
)
]
})
import { showMe } from "@observablehq/show-me"
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.
