This code creates a simple bar chart using the D3.js...

August 29, 2025 at 04:45 AM

This code creates a simple bar chart using the D3.js (Data-Driven Documents) library. Here's a detailed breakdown of what each part of the code does:

Data Initialization:
```
const data = [10, 20, 30, 40, 50];
```
- An array of numerical data is created, which represents the values of the bars in the chart.
SVG Canvas Setup:
```
const width = 500;
const height = 200;
const svg = d3.select("body")
              .append("svg")
              .attr("width", width)
              .attr("height", height);
```
- An SVG (Scalable Vector Graphics) element is created and added to the <body> of the HTML document.
- The svg element has a defined width of 500 pixels and height of 200 pixels, which serves as the canvas for drawing graphics.
Bar Creation:
```
svg.selectAll("rect")
   .data(data)
   .enter()
   .append("rect")
   .attr("x", (d, i) => i * 50)
   .attr("y", d => height - d * 4)
   .attr("width", 40)
   .attr("height", d => d * 4)
   .attr("fill", "teal");
```
- svg.selectAll("rect"): Selects all rect elements within the svg (none exist initially).
- .data(data): Binds the data array to the selection.
- .enter(): Adds new elements to match the data.
- .append("rect"): Appends a rectangle (<rect>) for each data point.
- .attr("x", (d, i) => i * 50): Sets the x-coordinate of each rectangle. The i (index) is multiplied by 50 to space the bars evenly.
- .attr("y", d => height - d * 4): Positions the top of the rectangle based on the value d (the data value), scaled by 4. The subtraction from height ensures the bars grow upward instead of downward.
- .attr("width", 40): Sets the width of each rectangle to 40 pixels.
- .attr("height", d => d * 4): Sets the height of each rectangle based on the data value, scaled by 4.
- .attr("fill", "teal"): Fills the bars with a teal color.

Result:

A bar chart with 5 bars will be displayed.
The height of each bar corresponds to the value in the data array, scaled by 4.
The bars are spaced 50 pixels apart horizontally, with each bar being 40 pixels wide.
The bars are colored teal.

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