Created
June 24, 2018 23:37
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this is notes about the d3 portion of the fcc code camp
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| d3 on fcc won't let be me |
din callback function as argument refers to the data point- used string literal for interpolation with automatic return
`${d} USD`
The D3 text() method can take a string or a callback function as an argument:
selection.text((d) => d)
<body>
<script>
const dataset = [12, 31, 22, 17, 25, 18, 29, 14, 9];
d3.select("body").selectAll("h2")
.data(dataset)
.enter()
.append("h2")
.text(d => `${d} USD`);
</script>
</body>
- can get in-line styles via method
.style('color', 'red) - sets style for all elements in the selection
<body>
<script>
const dataset = [12, 31, 22, 17, 25, 18, 29, 14, 9];
d3.select("body").selectAll("h2")
.data(dataset)
.enter()
.append("h2")
.text(d => d + " USD")
.style('font-family', 'verdana');
</script>
</body>
- woah this is cool
selection.style("color", (d) => {
/* Logic that returns the color based on a condition */
});
- used ternary here for readability with in-line
<body>
<script>
const dataset = [12, 31, 22, 17, 25, 18, 29, 14, 9];
d3.select("body").selectAll("h2")
.data(dataset)
.enter()
.append("h2")
.text((d) => (d + " USD"))
.style('color', d => d < 20 ? 'red' : 'green' );
</script>
</body>
https://learn.freecodecamp.org/data-visualization/data-visualization-with-d3/add-classes-with-d3
.attr()is similar to.style()because it can take in a callback function as an arg and it uses key-value pairs- d3 has
.attr()to add any attribute to an element - adds class of 'container' :
selection.attr("class", "container"); - can assign multiple classnames to that target selection via space separated (stack)
<style>
.bar {
width: 25px;
height: 100px;
display: inline-block;
background-color: blue;
}
</style>
<body>
<script>
const dataset = [12, 31, 22, 17, 25, 18, 29, 14, 9];
d3.select("body").selectAll("div")
.data(dataset)
.enter()
.append("div")
.attr('class', 'bar');
</script>
</body>
- can create pretty slick graph fairily easily ...
- dynamic height use
- alright add margin between the elements
- can multiple the height in-line, which is nice
after:
https://learn.freecodecamp.org/data-visualization/data-visualization-with-d3/learn-about-svg-in-d3
- scalable in scalable vector graphic means that it won't be pixelated on any screen
added svg, still need to style ->-> not sure
<style>
svg {
background-color: pink;
}
</style>
<body>
<script>
const dataset = [12, 31, 22, 17, 25, 18, 29, 14, 9];
const w = 500;
const h = 100;
const svg = d3.select("body")
// Add your code below this line
.append('svg')
.style('height', h)
.style('width', (d) => w + 'px')
// Add your code above this line
</script>
</body>
- interestingly, width and height attributes don't have any units
-> it'll be 5:1 anywhere, cool - before was making the istake of adding a px at the end
<style>
svg {
background-color: pink;
}
</style>
<body>
<script>
const dataset = [12, 31, 22, 17, 25, 18, 29, 14, 9];
const w = 500;
const h = 100;
// attr feels a lot like jquery here
const svg = d3.select("body")
.append('svg')
.attr('height', h)
.attr('width', w);
</script>
</body>
https://learn.freecodecamp.org/data-visualization/data-visualization-with-d3/display-shapes-with-svg
- coordinates are done just via attributes as well
<body>
<script>
const dataset = [12, 31, 22, 17, 25, 18, 29, 14, 9];
const w = 500;
const h = 100;
const svg = d3.select("body")
.append("svg")
.attr("width", w)
.attr("height", h)
.append("rect")
.attr("width", 25)
.attr("height", 100)
.attr("x", 0)
.attr("y", 0)
</script>
</body>
rectsmust be appended to an svg element before appended to the body
<body>
<script>
const dataset = [12, 31, 22, 17, 25, 18, 29, 14, 9];
const w = 500;
const h = 100;
const svg = d3.select("body")
.append("svg")
.attr("width", w)
.attr("height", h);
svg.selectAll("rect")
.data(dataset)
.enter()
.append('svg') /* need to first append svg before rect */
.append('rect')
.attr("x", 0)
.attr("y", 0)
.attr("width", 25)
.attr("height", 100);
</script>
</body>
- loop through using a callback
- don't need to write a for-loop because enter() already go through the data
<body>
<script>
const dataset = [12, 31, 22, 17, 25, 18, 29, 14, 9];
const w = 500;
const h = 100;
const svg = d3.select("body")
.append("svg")
.attr("width", w)
.attr("height", h);
svg.selectAll("rect")
.data(dataset)
.enter()
.append("rect")
.attr("x", (d, i) => i * 30) /* es6 implicit return */
.attr("y", 0)
.attr("width", 25)
.attr("height", 100);
</script>
</body>
- can also return data value in the callback
<body>
<script>
const dataset = [12, 31, 22, 17, 25, 18, 29, 14, 9];
const w = 500;
const h = 100;
const svg = d3.select("body")
.append("svg")
.attr("width", w)
.attr("height", h);
svg.selectAll("rect")
.data(dataset)
.enter()
.append("rect")
.attr("x", (d, i) => i * 30)
.attr("y", 0)
.attr("width", 25)
.attr("height", (d, i) => d * 3);
</script>
</body>
https://learn.freecodecamp.org/data-visualization/data-visualization-with-d3/invert-svg-elements
mis typically the multiplier for the data relationship to the actual ratio-
In general, the relationship is y = h - m * d, where m is the constant that scales the data points.
- wanted to make the multiplication more explicit with parens
- have to accomodate how d3 scales things with the top upper being 0,0 by subtracting from height
<body>
<script>
const dataset = [12, 31, 22, 17, 25, 18, 29, 14, 9];
const w = 500;
const h = 100;
const svg = d3.select("body")
.append("svg")
.attr("width", w)
.attr("height", h);
svg.selectAll("rect")
.data(dataset)
.enter()
.append("rect")
.attr("x", (d, i) => i * 30)
.attr("y", (d, i) => h - (3 * d))
.attr("width", 25)
.attr("height", (d, i) => 3 * d);
</script>
</body>
fillattribute is what makes up the elements
<body>
<script>
const dataset = [12, 31, 22, 17, 25, 18, 29, 14, 9];
const w = 500;
const h = 100;
const svg = d3.select("body")
.append("svg")
.attr("width", w)
.attr("height", h);
svg.selectAll("rect")
.data(dataset)
.enter()
.append("rect")
.attr("x", (d, i) => i * 30)
.attr("y", (d, i) => h - 3 * d)
.attr("width", 25)
.attr("height", (d, i) => 3 * d)
.attr('fill', 'navy')
</script>
</body>
- Not sure why
dreturns itself but ok, guess it could be anything - Weird have to subtract to go HIGHER
<body>
<script>
const dataset = [12, 31, 22, 17, 25, 18, 29, 14, 9];
const w = 500;
const h = 100;
const svg = d3.select("body")
.append("svg")
.attr("width", w)
.attr("height", h);
svg.selectAll("rect")
.data(dataset)
.enter()
.append("rect")
.attr("x", (d, i) => i * 30)
.attr("y", (d, i) => h - 3 * d)
.attr("width", 25)
.attr("height", (d, i) => 3 * d)
.attr("fill", "navy");
svg.selectAll("text")
.data(dataset)
.enter()
.append('text')
.attr('x', (d, i) => i * 30)
/* three units higher is subtraction */
.attr('y', (d, i) => h - (3 * d) - 3)
.text(d => d) /* returns d data value */
</script>
<body>
https://learn.freecodecamp.org/data-visualization/data-visualization-with-d3/style-d3-labels
- even text has a
fillcolor property
<body>
<script>
const dataset = [12, 31, 22, 17, 25, 18, 29, 14, 9];
const w = 500;
const h = 100;
const svg = d3.select("body")
.append("svg")
.attr("width", w)
.attr("height", h);
svg.selectAll("rect")
.data(dataset)
.enter()
.append("rect")
.attr("x", (d, i) => i * 30)
.attr("y", (d, i) => h - 3 * d)
.attr("width", 25)
.attr("height", (d, i) => d * 3)
.attr("fill", "navy");
svg.selectAll("text")
.data(dataset)
.enter()
.append("text")
.text((d) => d)
.attr("x", (d, i) => i * 30)
.attr("y", (d, i) => h - (3 * d) - 3)
.style('font-size', '25px')
.style('fill', 'red')
</script>
</body>
- add a class via attr
<style>
.bar:hover {
fill: brown;
}
</style>
<body>
<script>
const dataset = [12, 31, 22, 17, 25, 18, 29, 14, 9];
const w = 500;
const h = 100;
const svg = d3.select("body")
.append("svg")
.attr("width", w)
.attr("height", h);
svg.selectAll("rect")
.data(dataset)
.enter()
.append("rect")
.attr("x", (d, i) => i * 30)
.attr("y", (d, i) => h - 3 * d)
.attr("width", 25)
.attr("height", (d, i) => 3 * d)
.attr("fill", "navy")
.attr('class', 'bar')
svg.selectAll("text")
.data(dataset)
.enter()
.append("text")
.text((d) => d)
.attr("x", (d, i) => i * 30)
.attr("y", (d, i) => h - (3 * d) - 3);
</script>
</body>
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https://learn.freecodecamp.org/data-visualization/data-visualization-with-d3/work-with-data-in-d3
.data()method attaches data to selected elementsenter()seems to fill in the gaps fordata()attachenter()seems kind of like a looper, for each item in dataset