Multidimensional boolean array checking if all true in Javascript

Question

I have a multidimensional array of bools, with each element set to true:

var boolarray= $.extend(true, [], board);

board is a 3x3 multidimensional array of strings. boolarray is simply a deep copy of this.

     for (var i=0; i < boolarray.length; i++) {
              boolarray[i]
              for (var j=0; j < boolarray[i].length; j++) {
                boolarray[i][j] = true;
              };
            };

This gives me:

boolarray = [true,true,true,true,true,true,true,true,true]

I want to check if all elements are true and return if this is the case. However my method below does not work.

if (boolarray == true)
{
console.log("all elements in boolarray are true, return true ")
return true;
}
else 
{
console.log("not all elements in boolarray are true, return false")
return false;
}

Any ideas of how I should check if boolarray is all true?

just iterate all rows and columns and if any element = false return false else return true... If you wanted to make it a function that was easy to call then use prototype on the board class which would expose an isAllTrue method — Paul Sullivan, Apr 10 '12 at 22:07
@Paul, and if the first cell is true, you are returning true? you need to search the entire array, and then return true. — Tyymo, Apr 10 '12 at 22:08
no if all iteraations of the loop have failed return true (all are true) — Paul Sullivan, Apr 10 '12 at 22:17
and see my bitwise alternative to all the Log(On) algorithms — Paul Sullivan, Apr 10 '12 at 22:17
Note that the line boolarray[i] (immediately after the for loop's opening {) doesn't do anything. — nnnnnn, Apr 10 '12 at 22:17

Click-Rex · Accepted Answer · 2012-04-10 22:26:29Z

up vote 1 down vote accepted

You would need to loop through the array again to check all the values; in a very similar way to how you assigned them:

for (var i=0; i < boolarray.length; i++) {
    for (var j=0; j < boolarray[i].length; j++) {
        if (boolarray[i][j] == false) {
            return false;
        }
    };
}; 

return true;

edited Apr 10 '12 at 22:26

answered Apr 10 '12 at 22:08

Click-Rex
1,299721

1

This worked, thanks. – Kirberry Apr 10 '12 at 22:20

add a comment |

2 revs · Answer 2 · 2012-04-10 22:22:33Z

Use .every()...

var boolarray = [true,true,true,true,true,true,true,true,true];

boolarray.every(Boolean);

DEMO: http://jsfiddle.net/gFX7X/

If the only purpose of the first loop was to create the second, then you could skip it and do this...

var boolarray = [[true, true, true], 
                 [true, true, true], 
                 [true, true, true]];

boolarray.every(function(arr) {
    return arr.every(Boolean)
});

DEMO: http://jsfiddle.net/gFX7X/1/

Paul Sullivan · Answer 3 · 2012-04-10 22:16:09Z

up vote 3 down vote

As an alternative to using a boolean array why not use a simple Hexidecimal number to store your board (and then use bit manipulation to change/test) i.e.

000 000 001

==

1decimal

111 111 111

==

511 (256 + 128 + 64 + 32 + 16 + 8 + 4 + 2 + 1)

Setting a board position true or false would then become a bit manipulation and testing would become as simple as parseInt = 511...

see bit manipulation in javascript

answered Apr 10 '12 at 22:16

Paul Sullivan
2,3131820

This is interesting I will look into this for future learning, thanks. – Kirberry Apr 10 '12 at 22:20

No problem - note that this method will require about as much coding but will be much faster (parseInt is optimised in the javascript engine, not Log(On) i.e. the bigger the array the longer it takes worst case and smaller memory footprint – Paul Sullivan Apr 10 '12 at 22:27

Additonally this works for all instances where you would have to iterate the array to test i.e. 'are all values false' = parseInt == 0? and 'is any bit true' = parseInt > 0 – Paul Sullivan Apr 10 '12 at 22:47

add a comment |

Tyymo · Answer 4 · 2012-04-10 22:08:10Z

up vote 1 down vote

Write a function that runs a loop on a given parameter (our 2d array), and checks each cell if true. If not, return false. After the loop, return true;

answered Apr 10 '12 at 22:08

Tyymo
1,07221238

add a comment |

Dion · Answer 5 · 2012-04-10 22:08:49Z

bool alltrue = true;
for (var i=0; i < boolarray.length; i++) {
              boolarray[i]
              for (var j=0; j < boolarray[i].length; j++) {
                if(boolarray[i][j] != true) {
                    alltrue = false;
                }
              };
            };

jAndy · Answer 6 · 2012-04-10 22:12:25Z

ES5 notation example (simplified):

var foo = [ [true, true, true], [true, true], [true, true], [false, true], [true, true] ];

var boolarray = foo.every(function(level2, i) {
    return level2.every(function(bool) {
        return bool;
    });
});

This example exploits the fact that Array.prototype.every returns the result which returned from the loop function. As soon as a falsy value is returned, the iteration stops aswell.

^{If you need to stay compatible with old'ish browsers live IE6/7 you can just download one of the many ES5 shim librarys out there}

Ricardo Garza V. · Answer 7 · 2012-04-10 22:13:32Z

your variable named boolArray is an array and as long as it is not null, the code you wrote will se it as true, to get what you want you need something like this:

var boolArrayValue = true; // valor final a usar es boolarray value
for(var i = 0;i<boolarray.length;i++){
    for(var a = 0;a<boolarray[i].length;a++){
        boolArrayValue = boolArrayValue && boolarray[i][a];
    }
}

WereWolf - The Alpha · Answer 8 · 2012-04-10 22:23:05Z

up vote 1 down vote

boolarray = [true,true,true,true,true,true,true,true,true];
Array.prototype.isFalse=function(){
    for(var i=0;i<this.length;i++)
    {
        if(this[i]!=true) return false;
    }
    return true;
};
alert(boolarray.isFalse());

A fiddle here.

edited Apr 10 '12 at 22:23

answered Apr 10 '12 at 22:16

WereWolf - The Alpha
50k43781

prototyping Array is a grey area (I've read quite a lot of material that doesn't recommend due to many things (broken associative array behaviour and other broken ECMA stuff... handle Array.prototype with care – Paul Sullivan Apr 10 '12 at 22:35

Thanks for the advise. – WereWolf - The Alpha Apr 10 '12 at 22:36

add a comment |

Madbreaks · Answer 9 · 2012-04-10 22:15:54Z

up vote 0 down vote

for(var i in boolarray)
    if(!boolarray[i]) return false;

return true;

...this is based on your statement:

boolarray = [true,true,true,true,true,true,true,true,true]

Which is NOT a multi-dimensional array.

edited Apr 10 '12 at 22:15

answered Apr 10 '12 at 22:09

Madbreaks
8,69911432

his loop indicates he stores 3 booleans in an object array which is a multi dimensional array [i][j] – Paul Sullivan Apr 10 '12 at 22:30

@PaulSullivan - It's hard to know if the op's code is what it is, when he says "this is what it gives me" and indicates a flat array. I understand the loop, but the last bit of information (despite that) is that op's working with a 1-D array. – Madbreaks Apr 10 '12 at 22:34

boolarray[i][j] = true; – Paul Sullivan Apr 10 '12 at 22:36

@PaulSullivan Are you sure? You're operating under the assumption that the code snippet is what's being used to create boolarray? Why, when the op explicitly states var boolarray= $.extend(true, [], board);? Where's the code to initialize board? I on the other hand am assuming that one way or another, the op has what he has after code execution: boolarray = [true,true,true,true,true,true,true,true,true] – Madbreaks Apr 10 '12 at 22:42

but the iteration of the elements indicates it is a multi boolarray[i][j] = true;... I agree this is a moot point he could easily use a single dim array and just mulitplex the array. – Paul Sullivan Apr 10 '12 at 22:45

| show 1 more comment

lwburk · Answer 10 · 2014-01-23 21:48:46Z

A recursive version that checks nested arrays of arbitrary depth:

function deepEvery(arr, fn, _this) {
    return (function iterate(arr, i) {
        var len = arr && arr.length;
        if (!len || i >= len) {
            return false;
        }
        var first = arr[i] && typeof arr[i].splice === "function" 
            ? iterate(arr[i], 0) 
            : fn.call(_this || this, arr[i], i);
        i += 1;
        return !!first && (i >= len || iterate(arr, i));
    })(arr, 0);
}

Usage:

deepEvery([[true, true, true], 
           [true, true, true], 
           [true, true, true]], function(el, i) {
    return el;
});

Note that this allows for any type of check in the callback. If the function you pass to deepEvery returns false for any element, then the overall result is false; otherwise, the result is true. Example:

deepEvery([4, true, [6, [5, "F"], 6]], function(el, i) {
    return typeof el === "number";
});

vellotis · Answer 11 · 2014-07-26 17:23:48Z

Using jQuery.grep() and jQuery.map():

var flattenedBoolarray = $.map(boolarray, function recurs(n) {
    return ($.isArray(n) ? $.map(n, recurs): n);
});

if ($.grep(flattenedBoolarray, function(e, i){return e}, true).length) {
    // In case if any isn't true
} else {
    // In case if all are true
}

DEMO: http://jsfiddle.net/tYSu6/

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