如何在Javascript中循环一个arrays的object？

Question

For the below code,

const groupbysubject = {
                    "Mathematics":
                    [
                      {totalStudents: "23", average: "78", class: "2"},
                      {totalStudents: "25", average: "80", class: "3"}
                    ],
                    "English":
                    [
                      {totalStudents: "33", average: "98", class: "2"},
                      {totalStudents: "35", average: "99", class: "3"}
                    ],
                    "Science":
                    [
                      {totalStudents: "43", average: "65", class: "2"},
                    ]
                  }

                

var isEnglishPresent = Object.fromEntries(
                           Object.entries(groupbysubject).filter(
                             ([key, val])=> key.includes("English")
                            )
                        );

I want the following output:

"33" "98" "2" "35" "99" "3"

I have filtered the above groupbysubject object into isEnglishPresent object. How do I proceed further to iterate over isEnglishPresent and get the above output. Please help

Thank you.

Answer 1

You want a flat list of the values from the items inside the English key:

 const groupbysubject = { "Mathematics": [ {totalStudents: "23", average: "78", class: "2"}, {totalStudents: "25", average: "80", class: "3"} ], "English": [ {totalStudents: "33", average: "98", class: "2"}, {totalStudents: "35", average: "99", class: "3"} ], "Science": [ {totalStudents: "43", average: "65", class: "2"}, ] }; var englishData = groupbysubject.English.flatMap(item => Object.values(item)); console.log(englishData);

Answer 2

Assume you have an English array with N objects like below.

const English = [
  {totalStudents: "33", average: "98", class: "2"},
  {totalStudents: "35", average: "99", class: "3"},
  ...
]

Here's how you extract all the values and put it into an array.

English.map(item => Object.values(item)).flat()

Here's the output

["33", "98", "2", "35", "99", "3"]