This example demonstrates a bar chart that visualizes the frequency of each letter in a text excerpt from the Peter Piper nursery rhyme. It asynchronously loads the text file via `d3.text`, counts letters using JavaScript `Map` objects, and renders the chart with SVG rectangles. The visualization uses D3 v5 scales (`scaleLinear`, `scaleBand`) and axes (`axisBottom`, `axisRight`) to map counts to bar heights, with interactive updates triggered by `keyup` events on a textarea.
AI-generated descriptionLetter Count Bar Chart
In this demo, we asynchronously load a text file, use JavaScript to count the number of times each letter appears in that file, and generate a bar chart showing the letter count in D3.js v5.
This is meant to be an introductory demo to expose students to HTML, CSS, SVG, JavaScript, D3, Bl.ocks, Blockbuilder, and VizHub for the first time.
References
This example can be found at: Gist, Bl.ocks, Blockbuilder, VizHub
The starter template for this example can be found at: Gist
See the Wikipedia page Peter Piper Nursery Rhyme for the origins behind the text used in this example.
Inspirations
This example has undergone multiple iterations:
- Using Observable Notebook and D3v5: https://observablehq.com/d/28ba93f58fb82f49
- Using Bl.ocks and D3v5: https://bl.ocks.org/sjengle/1e23258249638a508426470a48ff2924
- Using Bl.ocks and D3v3: https://bl.ocks.org/sjengle/e8c0d6abc0a8d52d4b11
Below you can find videos related to an older version of this example. Please note that some content was discussed in-class only:
The original inspirations come from the following excellent tutorials on creating a bar chart in D3 for the first time:
D3 Bar Chart by Mike Bostock, Observable Notebook using D3v5, published on November 2017.
Let's Make a Bar Chart by Mike Bostock, Blog Post using D3v3, published on November 2013.
Making a Bar Chart by Scott Murray, Blog Post using D3v3, updated on December 2018.
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