使用 chart.js 和关联数组生成条形图

Question

I have associative array and I want to display it using Chart.JS library.

My Array:

array:4 [▼
  0 => array:3 [▼
    "faculty" => "Information Technology"
    "category" => "ELearning"
    "counter" => 2
  ]
  1 => array:3 [▼
    "faculty" => "Information Technology"
    "category" => "Webex"
    "counter" => 2
  ]
  2 => array:3 [▼
    "faculty" => "Masscom"
    "category" => "ELearning"
    "counter" => 3
  ]
  3 => array:3 [▼
    "faculty" => "Masscom"
    "category" => "Webex"
    "counter" => 3
  ]
]

What I am trying to do:

I am trying to show: - Faculties at the bottom as labels - For each faculty I want to show all the category and its counter

eg:

1) Information Technology has category ELearning with value 2 and has category Webex with value 2

2) Masscom has category ELearning with value 3 and has category Webex with value 3

JS Code:

var faculties = ['Information Technology', 'Masscom'];
var f = document.getElementById("mybarChart");
new Chart(f, {
    type: "bar",
    data: {
       labels: faculties,
       datasets: ....
    },
})

Answer 1

Essentially, you will need a data set for each of your categories. Each data set will need a data entry for each faculty.

Using the code below, you will get a chart that looks like this:

// this will get distinct faculty and sort
const faculties = [...new Set(data.map(v => v['faculty']))].sort();

// this will get distinct category and sort
const categories = [...new Set(data.map(v => v['category']))].sort();

const datasets = categories.map(category => ({
  label: category,
  data: faculties.map(faculty => {
    const value = data.find(v => v['faculty'] === faculty && v['category'] === category);

    return value['counter'];
  })
}));

const canvas = document.getElementById('mybarChart');

new Chart(canvas, {
  type: 'bar',
  data: {
    labels: faculties,
    datasets: datasets
  }
});

I created a jsfiddle to show the code running .