match a variable to an element inside an array of objects?

Question

i have a varable:

var name = "name";

this will be inside an array of objects i have:

    var all = [];
    $.each(results, function(i, item){
        all.push({
            rank: i + 1,
            username: item.TopicName,
            mentions: item.LastHourCount,
            totalcount: item.TotalCount,
            urlLg: item.LargeImageUrl,
            urlSm: item.SmallImageUrl,
            shortname: item.ShortName
        });

    });

I need to look through the array of objects and find the 'shortname' that matches the variable 'name'. the objects look like this:

Object[
  mentions: 21737
  rank: 2
  shortname: "name"
  totalcount: 59330
  urlLg: null
  urlSm: "http://i.cdn.turner.com/nba/nba/pulse/allstar/2012/img/images-small/howard.png"
  username: "lebron james"
],

once i find it set that to a variable: var showThis = all.[];

Inside the each function as it loops through the json file, is probably where to look for the name?

T.J. Crowder · Accepted Answer · 2012-02-09 14:38:19Z

3

I think I may be misunderstanding. If you just want to find the entry in all with a shortName matching name, then:

var match;
$.each(all, function() {
    if (this.shortName === name) {
        match = this;
        return false;
    }
});

That uses $.each to loop through the array. In the iterator callback, this will refer to the array element, so we just check this.shortName === name. The return false stops the each loop. If there's no match, match will keep its default value (undefined).

Or as a traditional for loop:

var match, index, entry;
for (index = 0; index < all.length; ++index) {
    entry = all[index];
    if (entry.shortName === name) {
        match = entry;
        break;
    }
});

answered Feb 9, 2012 at 14:38

T.J. Crowder

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4 Comments

Xtian Over a year ago

Quick question, is there an easy way to then grab the next object after the match? So a user clicks next button, which will then load the next object?

T.J. Crowder Over a year ago

@Xtian: Yes. If you read through the linked documentation, the iterator function we hand to each will receive two arguments (I didn't use them above) when called: The index of the item we're visiting, and a reference to it (e.g., function(index, item)). So if you find a match, then the next item after the match will be at all[index+1] (assuming the match wasn't at the very end).

Xtian Over a year ago

this makes sense, i added a var matchNext and put this in my if statement: matchNext = match[i + 1]; but this isn't working?

T.J. Crowder Over a year ago

@Xtian: See my comment above. You want to index into all, not match.

Šime Vidas · Accepted Answer · 2012-02-09 14:55:22Z

0

Underscore.js solution:

var showThis = _.find( all, function ( elem ) {
    return elem.shortname === name;
});

Plain JavaScript solution:

var showThis = all.filter( function ( elem ) {
  return elem.shortname === name;
})[ 0 ];

Btw, .filter() is an ES5 array iteration method. The ES5 array iteration methods are not implemented in IE8 and older versions. (You can easily polyfill them though.)

edited Feb 9, 2012 at 14:55

answered Feb 9, 2012 at 14:39

Šime Vidas

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8 Comments

T.J. Crowder Over a year ago

@Xtian: Note that Šime's used a feature of JavaScript taht won't exist on about half of the browsers people use in the wild; you'll have to shim it if you use it. Šime: meta.stackexchange.com/questions/118021/…

Šime Vidas Over a year ago

@T.J.Crowder "Half of the browsers" is a bit misleading. Only IE8 and IE7 are affected. Those two browsers comprise about 20-30% of page-views (depending on location).

T.J. Crowder Over a year ago

@Šime: No, half is about right, and much closer than 20-30%. I did the math in my answer to the linked question. (Also, IE6 is affected; remember that more than a quarter of Chinese web surfers use IE6; a number which is thankfully finally coming down.)

T.J. Crowder Over a year ago

@Šime: It's not just IE6. It's IE6, IE7, IE8, Firefox 3.x, and a bunch of others. You're casually ignoring no fewer than 30% of all web surfers even disregarding the Chinese market, and (all due respect) for no good reason. One sentence on an answer is what it takes to avoid setting a trap for someone to fall into. Why wouldn't you do that? Isn't the whole point of answering questions here to be helpful? Last word can be yours, I think we've beat this to death.

Šime Vidas Over a year ago

@T.J.Crowder Well, alright then. I'm going to include that note in my future answers.

|

bluish · Accepted Answer · 2012-02-10 14:41:09Z

0

var t={};

$.each(all, function(i, item){

  if (item['shortname']=="name") {
    t=this;
    return false;
  }

});

edited Feb 10, 2012 at 14:41

bluish

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answered Feb 9, 2012 at 14:38

Royi Namir

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2 Comments

Royi Namir Over a year ago

@T.J.Crowder yeah ... nevermind... if it was an html dom so i regullary make it jquery objkect....

T.J. Crowder Over a year ago

And why use item in one place, but this in another?

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