LinQ foreach in javascript/jquery

Question

How can I easily do these type of loops in Jquery or Javascript? Preferably without any other plugins.

string a = "";
foreach (var i in (from a in DbList1 select a.FieldA).Distinct())
{
   a += i + ", ";
}

and this

foreach (var i in DbList2)
{
   a += i.FieldB + ", ";
}

Loop number 2 could be solved like this atleast.

$.each(aData.DbList2, function (index, value) {
 a += value.FieldB;
);

Not 100% sure this is the most effective though

are you iterating upon an array and getting something from each element ? Better to post a sample question like **How to concatinate words in array ?** Syntax from other languages are just confusing. — Mritunjay, Jul 10 '15 at 11:36
hi please find this URL that may be help to you http://stackoverflow.com/questions/11887450/each-vs-for-loop-and-performance — Neo Vijay, Jul 10 '15 at 11:43
a sample of your source data would go a long way to getting help on how to do something with it - I take it, since you don't want any libraries (except the biggest piece of bloat in existence, jQueery) https://linqjs.codeplex.com/ is out of the question — Jaromanda X, Jul 10 '15 at 11:44

John R · Answer 1 · 2015-07-10T12:11:41.033

3

You can use map method for iterating array variable.

Code snippets:

var arr = jQuery.map( aData.DbList2, function(value) {
return value.FieldB;
});
//To get unique array variable
var uniqueArr = [];
$.each(arr, function (i, el) {
            if ($.inArray(el, uniqueArr) === -1) uniqueArr.push(el);
        });

edited Jul 10 '15 at 12:11

answered Jul 10 '15 at 11:44

John R

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how do you emulate the Distinct() function :p – Jaromanda X Jul 10 '15 at 11:46
Yea, how can Distinct or Unique as I read it's called in Jquery be implemented? – stibay Jul 10 '15 at 12:00

phuzi · Accepted Answer · 2015-07-10T12:04:19.887

2

Second one is easy enough to do in vanilla JavaScript:

var a = "";
for (var i = 0; i < DbList2.length; i++){
    a += DbList2[i].FieldB + ", ";
}

First one is a little trickier, but not impossible and can also be done with vanilla JS.

var a = "";
var uniques = [];

for (var i = 0; i < DbList1.length; i++ ){
    var fieldA = DbList1[i].FieldA;
    // check if we've already seen this value
    if (uniques.indexOf(fieldA) < 0)
    {
        // Nope, record it for future use
        uniques.push(fieldA)

        // and update the string.
        a += fieldA + ", ";
    }
}

edited Jul 10 '15 at 12:04

answered Jul 10 '15 at 11:56

phuzi

12,078
3
26
50

According to http://stackoverflow.com/questions/11887450/each-vs-for-loop-and-performance this seems to be very good performace. So is it an easy way to only add unique values to a? – stibay Jul 10 '15 at 12:02

LinQ foreach in javascript/jquery

2 Answers2