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Kevin Perese
Economic demographer by training; data and coding nerd at heart.
Public
Edited
Apr 20, 2023
Fork of Introduction to data wrangling and analysis in JavaScript — Session 1 Follow-along version
1
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burrito = ["chicken", 4.2, false, "avocado", 11.99, "beans"]
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// Access the fourth element in burrito:
burrito[3]
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// Find the length of the burrito array:
burrito.length
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// Find the index (position) of the value 4.2 in burrito:
burrito.indexOf("beans")
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droids = [
{name: "C-3PO", color: "gold", height: 167},
{name: "R2D2", color: "white/blue", height: 96},
{name: "BB-8", color: "white/orange", height: 26.4}
]
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// Find the length of the droids array:
droids.length
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// Find the value of "height" for the third element in droids (BB-8's height):
droids[2].height
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//or
droids[2]["height"]
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// Find the keys of the first element in the droids array:

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restaurantBills = [{bill: 49.51, tipPercent: 0.15},
{bill: 112.40, tipPercent: 0.22},
{bill: 68.25, tipPercent: 0.18},
{bill: 27.37, tipPercent: 0.12},
{bill: 50.18, tipPercent: 0.17}]
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// Calculate tips for each bill here:
restaurantBills.map(d => d.bill * d.tipPercent)
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nyc_water = FileAttachment("nyc_water.csv").csv({typed: true})
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nyc_water
Type Table, then Shift-Enter. Ctrl-space for more options.

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// Access the third element in the array:
nyc_water[2]
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// Access Consumption (HCF) from the ninth element in the array:
nyc_water[8]["Consumption (HCF)"]
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// Access Location from the 100th element in the array:
nyc_water[99].Location
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// Use Array.map and an arrow array to return and array with the ratio of Current Charges to Consumption (HCF):
prices = nyc_water.map(d => d["Current Charges"] / d["Consumption (HCF)"])
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Plot.plot({
marks: [
Plot.dot(nyc_water, {
x: "Consumption (HCF)",
y: "Current Charges",
fill: "purple",
r: "Consumption (HCF)"
})
],
x: { domain: [0, 50000] }
})
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// Create and customize a scatterplot of Consumption (HCF) and Current Charges from the nyc_water data:

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import { showMe } from "@observablehq/show-me"
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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.
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