Tuesday, January 31, 2012

wired output of the combination of $.each and jQuery.inArray function


My complete code:




jQuery.extend({

combinationCheck: function (p1position) {

var Combination = [1, 2, 3, 4, 5, 6, 7, 8];
Combination[0] = [1, 2, 3];
Combination[1] = [4, 5, 6];
Combination[2] = [7, 8, 9];
Combination[3] = [1, 4, 7];
Combination[4] = [2, 5, 8];
Combination[5] = [4, 6, 8];
Combination[6] = [1, 5, 9];
Combination[7] = [3, 5, 7];


$.each(p1position, function (index, value) {

var num = value;

if ($.inArray(String(value), Combination[1]) != '-1') {
alert("there");
}
else {
alert("not there");
}

});
});



so it works. If I were to set num to 5, it alerts "is there", and for 8 --> "not there". but the problem is I have another array.




p1position = [1,5];



and go through the array..




$.each(p1position,function(index,value){
var num = value;
//then call the jQuery.inArray function as written above, it always return not there. even though 5 is in the Combination[1] array.
});



I am so confused of trying to solve this problem for hours.

1 comment:

  1. The specific problem with your code that you're asking about is that you're turning the value into a string before the check:

    if ($.inArray(String(value), Combination[1]) != '-1') {
    // ^^^^^^^^^^^^^


    inArray does an === (strict equality) check, and "1" !== 1. That line should read:

    if ($.inArray(value, Combination[1]) !== -1) {


    Changes:


    Don't turn the value into a string.
    Compare the result with -1 (a number), not "-1" (a string). inArray returns a number.
    Use !== rather than != (this is mostly a matter of style, you can use != if you prefer).




    There are several other problems with that code, though.


    You're missing a }, so the code you say is your complete code doesn't parse.
    You're re-creating Combination every time the combinationCheck is called. If your goal is to create a Tic-Tac-Toe game, you're going to need to be able to retain the Combination state between checks.


    Here's a fairly minimal set of fixes:

    (function() {
    var Combination = [
    [1, 2, 3],
    [4, 5, 6],
    [7, 8, 9],
    [1, 4, 7],
    [2, 5, 8],
    [4, 6, 8],
    [1, 5, 9],
    [3, 5, 7]
    ];

    jQuery.extend({

    combinationCheck: function (p1position) {

    $.each(p1position, function (index, value) {

    if ($.inArray(value, Combination[1]) !== -1) {
    alert(value + " is there");
    }
    else {
    alert(value + " is NOT there");
    }

    });
    }
    });

    })();


    ...which given:

    jQuery.combinationCheck([1, 5]);


    ...reports that 1 is not found, but 5 is.

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