I want to get all the values that equal a certain number and count how many of each of the objects.
My code looks like this:
var countItems = {
"aa":"70",
"bb":"70",
"cc":"80",
"dd":"90",
"ee":"90",
"ff":"90"
}
Now what I want to do is count each on that is in the second half.
For example, there are two "70", one "80", and three 90. Then I can assign to variables:
var firstCounter = ?? // 2
var secondCounter = ?? // 1
var thirdCounter = ?? // 3
?? is I don't know what goes here.
If it was structed differently like the following, I could do it like this:
let firstCounter = 0;
for (let i = 0; i < countItems.length; i++) {
if (countItems[i].status === '70') firstCounter++;
}
let secondCounter = 0;
for (let i = 0; i < countItems.length; i++) {
if (countItems[i].status === '80') secondCounter++;
}
let thirdCounter = 0;
for (let i = 0; i < countItems.length; i++) {
if (countItems[i].status === '90') thirdCounter++;
}
But the thing is, my original code which is what I have is not structured like that, so I'm not sure how to adapt it.
How can I count the items in the original list (var countItems) so that I can find out how much each value is?
You could use Object.values(countItems) to get an array that looks like this: ["70","70","80","90","90","90"] then either use a for loop to conditionally increment whatever counters you want, or use something like Array.reduce or Array.filter to count the elements you need.
You could use reduce to create a counted hash map like so:
const countItems = [
{ data: 'aa', status: '70' },
{ data: 'bb', status: '70' },
{ data: 'cc', status: '80' },
{ data: 'dd', status: '90' },
{ data: 'ee', status: '90' },
{ data: 'ff', status: '90' },
];
const countedHash = countItems.reduce((acc, curr) => {
if (!acc[curr.status])
acc[curr.status] = 1
else
acc[curr.status] += 1
return acc
}, {})
/* print out the results */
console.log(countedHash)https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/reduce
You can access object keys like this :
countItems["aa"] // it will return "70"
You can also loop on the object (if you want to do as you did in your example) :
for (const item in countItems) {
console.log(countItems[item])
if (countItems[item] == "70") firstCounter++;
}