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08th Dec, 2019
Below are few major features of D3.js
Q1. What is D3.js?
Q2. What are applications of D3.js?
There are many applications or uses in using D3.js,
Q3. Enlist major adavantages and disadvantages of D3.js?
As a powerful visualization tool, D3.js has many advantages.
Some disadvantages of using D3.js,
Q4. Explain selections in D3?
The selection function in D3.js is used to select the DOM elements easily and apply some effects to them. It is a declarative method and operates on a set of nodes or an individual node. After selecting the elements/nodes, you can do changes like modifying its style, attributes, removing or adding an element, changing text/HTML content, etc.
D3.js provides two functions to do selections,
d3.select function selects the first matching element and d3.selectAll function selects all matching element.
//example d3.select(‘.itemClass’).style("background-color", "blue");
The above function selects the first element with class name ‘itemClass’ and changes its background color to blue.
The above function selects all the paragraphs and changes its background color to blue.
Q5. Explain transition in D3.js?
The transition function applies the given change to the selected DOM elements smoothly over a period of time instead of instantaneously. It is a key frame animation that uses predefined twinning and your own definitions. Transition supports most of the selection methods like style, attar, etc.
d3.select ("body").transition ().style ("color", "red");
The above function selects the element of class body and changes its color to red smoothly over a period of time (the default duration is 250ms). The developers can set the duration of transition by the duration () function.
d3.select ("body").transition ().duration (700).style("color", "green");
In the above function the transition occurs for 700ms from start default frame to the end frame of green colored body.
Q6. How to format the date in d3.js?
The time format functions in D3.js is used to format the date.
To format the date in string into datetime object use the following function,
> var FormatDate = d3.timeFormat("%Y-%m-%d"); > FormatDate(“2020-01-01”).parse Wed Jan 01 2020 00:00:00 GMT-0600 (Central Standard Time) To get the current date in D3.js, var formatTime = d3.timeFormat("%B %d, %Y"); formatTime(new Date); //returns “Jan 06 2020”
There are a lot of format specifiers in d3.js to format the date like %a, %b, etc for to get abbreviated weekday name, abbreviated month, etc
Q7. How to alter zoom modes in d3.js?
With the help of the d3.zoom function, we can change the zoom behavior.
d3.zoom() function creates the zoom behavior that you can apply to the selected elements
To apply the zoom behavior on selected element,
To set zoom transform on the selected items,
selection.call(zoom.transform, d3.zoomIdentity); //it sets the identity transform for the selected items.
To translate the zoom transform for the selected item,
zoom.translateBy(selection, x, y); //it translates by the given x & y values.
To translate the zoom transform of the selected item to a given point,
zoom.translateTo(selection, x, y[, p]) //it translates the position(x, y) to the given point p.
Like these, there are many default zoom properties to change the zoom of a selected item in the d3 library.
Q8. What D3.js selects method does?
The select method in d3.js accepts a string and returns the first element that matches the string. If multiple elements match the string, then it returns the first element. If no element matches the string then it returns empty selection.
d3.select ("element") //syntax
<html> <head> <body> <div>Example for select function <script> // Calling the select() function var a = d3.select("div").text(); // Getting the selected element console.log(a); //returns “Example for select function” </script> </body> </html> </pre>
Q9. What different types of slider available in d3.js?
We define different types of slider functions available in d3.js are,
d3.slider(); //creates default slider
d3.sliderLeft([scale]); //creates vertical slider. Ticks to left
d3.sliderBottom([scale]); //creates horizontal slider. Ticks to bottom
d3.sliderRight([scale]); //creates vertical slider. Ticks to right
d3.sliderTop([scale]); //creates horizontal slider. Ticks to top
d3.sliderVertical([scale]); //creates vertical slider like sliderLeft
d3.sliderHorizontal([scale]); //creates vertical slider like sliderBottom
Q10. What command used to create simple axis in d3.js?
D3.js provides the axes function to create a simple axis. An axis has simple lines, ticks, and labels.
d3.axisTop(); // Creates top horizontal axis.
d3.axisRight(); //Creates vertical right-oriented axis.
d3.axisBottom(); //Creates bottom horizontal axis.
d3.axisLeft(); //Creates left vertical axis.
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