How to loop through multiple arrays in JavaScript?

Question

I have this array:

{"Los Angeles, CA":["East Los Angeles","Florence","Florence-Firestone","Los Feliz","West Los Angeles"]}

But my code prints only "Los Angeles, CA", without child array strings...

function search4Location(query = true) {
    $.ajax({
        url: '/work/ajax/regions.php' + (query ? '?q=' + $("#searchLocation").val() : ''),
        dataType: 'json',
        success: function(data) {
            var datalen = data.length;
            $("#region").html('');
            if (query == true) {
                for (var i = 0; i < datalen; i++) {alert(123);
                    $("#region").append('<option>' + data[i] + '</option>');
                    var datalen2 = data[i].length;
                    for (var ii = 0; ii < datalen2; ii++) {
                        $("#region").append('<option>—— ' + data[i][ii] + '</option>');
                    }
                }
            } else {
                for (var i = 0; i < datalen; i++) {
                    $("#region").append('<option>' + data[i] + '</option>');
                }
            }
        } 
    });

    return false;
}

How to display them?

Is the query var meant to relate to anything? I don't see it being set. You probably want to check the return is an array, the iterate it if so, if not print it? — Carl, Sep 26 '16 at 13:57
_“I have this array”_ – that is not an array, it’s an object. — CBroe, Sep 26 '16 at 13:57
Given that data, the code shouldn't do anything because it's an object which doesn't have the `length` property. — JJJ, Sep 26 '16 at 13:58
@CBroe This guy is likely more familiar with PHP, where arrays have key value pairs, and are converted to objects in JSON. — Howzieky, Sep 26 '16 at 13:59
@Howzieky what's the relevance to this issue? php arrays don't use `length` and op is clearly not looking for the outer array if that was the case anyway — charlietfl, Sep 26 '16 at 14:14
I suppose it's not relevant to the issue (though it may help OP with his google searches in the future). I was just explaining why OP might have called it an array instead of an object, and where the confusion would come from — Howzieky, Sep 26 '16 at 17:52
This is pretty close: https://stackoverflow.com/a/44249809/2943403 — mickmackusa, Jan 19 '19 at 00:46

score 0 · Answer 1 · edited Jan 19 '19 at 00:20

I found the way!

function search4Location(query = true) {
    $.ajax({
        url: '/work/ajax/regions.php' + (query ? '?q=' + $("#searchLocation").val() : ''),
        dataType: 'json',
        success: function(data) {
            $("#region").html('');
            if (query == true) {
                for (var make in data) {
                    $("#region").append('<option>' + make + '</option>');
                    for (var i = 0; i < data[make].length; i++) {
                        $("#region").append('<option>— ' + data[make][i] + '</option>');
                    }
                }
            } else {
                var datalen = data.length;
                for (var i = 0; i < datalen; i++) {
                    $("#region").append('<option>' + data[i] + '</option>');
                }
            }
        } 
    });

    return false;
}

Please include an explanation with every answer that you post. Stack Exchange sites are more than just collections of snippets. The goal is to start with correct solutions then educate researchers so that they can apply the gained knowledge to more than just the narrow scope of the question. — mickmackusa, Jan 19 '19 at 00:23

How to loop through multiple arrays in JavaScript?

1 Answers1