si619 lab4 notes

Running a Python Server

For security reasons, browsers don't allow loading external files such as our data.csv. There are a few different ways to fix this, one of which is to set up a local server.

• On the mac, open terminal and navigate to the "inclass" folder. Then execute on of the above commands depending on your python version. InthePowerShellwindow,type:

python -m SimpleHTTPServer 8000

OR

python3 -m http.server

• In Google Chrome, type: localhost:8000 in your browser address bar and hit enter.

scale functions: D3 offers several useful functions that do the calculations for us. These are broadly called scale functions.

scale types: D3 offers the following types of scale types:

• Scales with continuous input and continuous outputs (e.g., scaleLinear, scaleTime)
• Scales with continuous input and discrete outputs (e.g., scaleQuantile )
• Scales with discrete input and discrete outputs (e.g., scaleOrdnial, scaleBand)

forEach(): 方法对数组的每个元素执行一次提供的函数。

var array1 = ['a', 'b', 'c'];

array1.forEach(function(element) {
  console.log(element);
});

// expected output: "a"
// expected output: "b"
// expected output: "c"