How do I take an array of strings and filter them?

Question

I have an array of strings in jQuery. I have another array of keywords that I want to use to filter the string array.

My two arrays:

    var arr = new Array("Sally works at Taco Bell", "Tom drives a red car", "Tom is from Ohio", "Alex is from Ohio");

    var keywords = new Array("Tom", "Ohio");

How can I filter the arr array using the keywords array in jQuery? In this situation it would filter out "Sally works at Taco Bell" and keep the rest.

Below is the actual code I am using.

var keywords= [];
var interval = "";
var pointer = '';
var scroll = document.getElementById("tail_print");

$("#filter_button").click(
function(){
    var id = $("#filter_box").val(); 
    if(id == "--Text--" || id == ""){
        alert("Please enter text before searching.");
    }else{
        keywords.push(id);
        $("#keywords-row").append("<td><img src=\"images/delete.png\" class=\"delete_filter\" /> " + id + "</td>");
    }
}
);

$(".delete_filter").click(
function(){
   ($(this)).remove(); 
}
);

function startTail(){
clearInterval(interval);
interval = setInterval(
function(){
    $.getJSON("ajax.php?function=tail&pointer=" + pointer + "&nocache=" + new Date(),
        function(data){
            pointer = data.pointer;
            $("#tail_print").append(data.log);
            scroll.scrollTop = scroll.scrollHeight;
        });
}, 1000);
}

The whole purpose of this is to allow the user to filter log results. So the user performs an action that starts startTail() and $.getJSON() retrieves a JSON object that is built by a PHP function and prints the results. Works flawlessly. Now I want to give the user the option to filter the incoming tailing items. The user clicks a filter button and jQuery takes the filter text and adds it to the keywords array then the data.log from the JSON object is filtered using the keywords array and then appended to the screen.

I also have a delete filter function that isn't working. Maybe someone can help me with that.

Solution 1

$.grep( arr, $.proxy(/./.test, new RegExp(keywords.join("|"))));

without jQuery:

arr.filter(/./.test.bind(new RegExp(keywords.join("|"))));

Solution 2

jQuery's word for "filter" is grep

var arr = ["Sally works at Taco Bell", "Tom drives a red car", "Tom is from Ohio", "Alex is from Ohio"];
var keywords = ["Tom", "Ohio"];

var regex = new RegExp(keywords.join("|"));

result = $.grep(arr, function(s) { return s.match(regex) })

Solution 3

var filtered = [];
var re = new RegExp(keywords.join('|'));

for (var i=0; i<arr.length; i++) {
    if (re.search(arr[i])) {
        filtered.append(arr[i]);
    }
}

UPDATE

Since there's better answers here from a jQuery perspective, I modified my answer to a vanilla JavaScript approach, just for those who might need to do this without jQuery.

Solution 4

Top of head, and untested. As a jQuery plugin:

(function($) {

    $.foo = function(needle, haystack) {
        return $.grep(haystack, function () {
            var words = this.split(' '),
                flag = false
                ;

            for(var i=0; i < words.length; i++) {
                flag = $.inArray(words[i], needle);
                if (flag) { break; }
            }

            return flag;                
        });
    };

})(jQuery);

Then you can (supposedly) run that like:

var bar = $.foo(keywords, arr);

View more solutions

Comments

[kapa]

@Xeon06 The jquery tag was fine, it indicates that the OP accepts solutions based on jQuery methods.

[Richard Neil Ilagan]

... and I seriously have to think of regex'es top of head. nicely done. :D it'd be nice to slap it on with the $.grep() function though. +1

[jondavidjohn]

+1 very nice solution, write out the loop, and no jQuery needed :D

[Chris Pratt]

Best answer here in my opinion, even though it does borrow somewhat from mine ;).

[jondavidjohn]

Might want to include a hasOwnProperty() if you're using for..in I would honestly just use a regular for, you are dealing with arrays not objects. developer.mozilla.org/en/JavaScript/Reference/Global_Objects‌​/…

[Esailija]

@qwertymk well I have only tested in IE7 and chrome, no reason it wouldn't work in other browsers though. If you are using the second one in a legacy browser you need to shim .filter and .bind from MDN for example.

[georg]

@ChrisPratt: I didn't borrow anything.

[mozzbozz]

I am using this in Qt / QML to filter the content of a ComboBox depending on the text in the TextField next to it: Works like charm, just one line of code for filtering and it's really fast (no noticeable delay; got about 500 Strings to be filtered). First tried to adapt some bloaty typeahead javascript libraries but could not get it work. Your one line of code: Perfect -> Thanks! :D