array intersection with nested arrays

Question

Pretty new to functional javascript, so please bear with me.

Edited for more information.

I have an array that is being created from a csv file using:

var url = "URL-TO-CSV/report.csv";

var request = new XMLHttpRequest();  
request.open("GET", url, false);   
request.send(null);  

var csvData = new Array();
var jsonObject = request.responseText.split(/\r?\n|\r/);
for (var i = 0; i < jsonObject.length; i++) {
csvData.push(jsonObject[i].split(','));
}

Which results in an array of arrays, not keyed pairs.

[
  ['stringID-1',"string","string","string","string"],
  ['stringID-2',"string","string","string","string"],
  ['stringID-3',"string","string","string","string"]
]

And another array generated from a list of id's to be matched which is currently using jQuery (because I haven't figured out raw Javascript for it yet), like so:

 $("input:checkbox:not(:checked)").each(function () {
     
        var $this = $(this);
        matchData.push($this.attr("id"));
           
})

Which results in the below type array.

['stringID-1','stringID-3']

I have tried varying filter syntax but to no avail. If I don't get an error I get an empty array.

I need to intersect the two and return an array of the matching arrays from csvData so I can then parse it to HTML in an each loop.

I cannot seem to be able to figure this out and would love some direction. Thanks in advance

You might have to explain a little more. does matchData contain a list of arrays of ids that you want concated? — Colin Hale
– Colin Hale, Commented Sep 14, 2022 at 18:02
@ggorlen I have added the portions of working code I am using to this point, thank you. — chris
– chris, Commented Sep 14, 2022 at 18:25
@ColinHale no matchData contains a list of ID's of on form checkboxes. Those are to be cross referenced with the other array, to return only the arrays whose [0] match the id's listed in the matchData array. I want the returned array to be in the same format as csvData, but only containing arrays with matching string id's. thanks — chris
– chris, Commented Sep 14, 2022 at 18:29

Jared Farrish · Accepted Answer · 2022-09-14 18:04:40Z

3

I think all you need is a filter to restrict to rows where the first indexed is found in the other array:

let csvData = [
    ['item-to-match-string-id-1', "string data", "string data", "string data"],
    ['item-to-match-string-id-2', "string data", "string data", "string data"],
    ['item-to-match-string-id-3', "string data", "string data", "string data"],
    ['item-to-match-string-id-4', "string data", "string data", "string data"],
    ['item-to-match-string-id-5', "string data", "string data", "string data"],
]

let matchData = ['item-to-match-string-id-2','item-to-match-string-id-5']

let matching = csvData.filter(row => matchData.includes(row[0]))

console.log(matching)

answered Sep 14, 2022 at 18:04

Jared Farrish

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1 Comment

Jared Farrish Over a year ago

The logic of the lookup itself will need to take into account if the two comparison values are formatted differently. This just looks at the first array value and sees if the value matches a value in the other array (case sensitive).

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