How come this 2-dimensional array is adding elements unexpectedly?

Question

How come this 2-dimensional array is adding elements unexpectedly?

I just realized my error where the tempRndNumber was being reset in the inner loop. Although, I am still encountering an issue where "," characters are appearing in the array.

The goal is to create a 2D array that is populated only when a random number meets a specific condition (rnd >= 7). However, the current code is filling the 2D array with a combination of "," and the numbers that meet the criteria.

var tempAllRndNumbers = [];
    for (var i = 0; i < 10; i++) {
        for (var j = 0; j < 10; j++) {
            var tempRndNumber = [];
            var rndNumber = Math.floor(Math.random() * 10);
            if (rndNumber >= 7) {
                tempRndNumber.push(rndNumber);
            }
        }
        tempAllRndNumbers.push(tempRndNumber);
    }

My expectation was that tempAllRndNumbers would only contain numbers 7 and above. However, I am observing that the 2D array is filled with both "," and numbers 7 and above.

javascript arrays

Answer 1

Answer №1

By resetting the tempRndNumber array to empty within the j loop, it will only store a number if the last iteration was >= 7. To resolve this, move the initialization of tempRndNumber outside of the innermost loop:

var allTempRndNumbers = [];
    for (var x = 0; x < 10; x++) {
        var tempRndNumber = [];
        for (var y = 0; y < 10; {
            var randomNum = Math.floor(Math.random() * 10);
            if (randomNum >= 7) {
                tempRndNumber.push(randomNum);
            }
        }
        allTempRndNumbers.push(tempRndNumber);
    }

Answer 2

By resetting the tempRndNumber array to empty within the j loop, it will only store a number if the last iteration was >= 7. To resolve this, move the initialization of tempRndNumber outside of the innermost loop:

var allTempRndNumbers = [];
    for (var x = 0; x < 10; x++) {
        var tempRndNumber = [];
        for (var y = 0; y < 10; {
            var randomNum = Math.floor(Math.random() * 10);
            if (randomNum >= 7) {
                tempRndNumber.push(randomNum);
            }
        }
        allTempRndNumbers.push(tempRndNumber);
    }

Answer 3

Answer №2

It appears that a crucial check was omitted to verify the presence of values in the tempRndNumber array. Consequently, an empty array is being inadvertently pushed into the tempAllRndNumbers array, resulting in the presence of redundant ',' characters. This situation arises from indexes lacking corresponding values within the array.

Answer 4

It appears that a crucial check was omitted to verify the presence of values in the tempRndNumber array. Consequently, an empty array is being inadvertently pushed into the tempAllRndNumbers array, resulting in the presence of redundant ',' characters. This situation arises from indexes lacking corresponding values within the array.

Answer 5

Answer №3

It might be better to avoid resetting the tempRndNumber variable in every iteration of the inner loop. Consider the following code snippet:

var tempAllRndNumbers = [];
for (var i = 0; i < 10; i++) {
    var tempRndNumber = [];
    for (var j = 0; j < 10; j++) {
        var rndNumber = Math.floor(Math.random() * 10);
        if (rndNumber >= 7) {
            tempRndNumber.push(rndNumber);
        }
    }
    tempAllRndNumbers.push(tempRndNumber);
}

UPDATE: To achieve the desired output, make sure to loop through both arrays. Check out the solution here:

http://jsfiddle.net/jessikwa/1fbq0woo/

Answer 6

It might be better to avoid resetting the tempRndNumber variable in every iteration of the inner loop. Consider the following code snippet:

var tempAllRndNumbers = [];
for (var i = 0; i < 10; i++) {
    var tempRndNumber = [];
    for (var j = 0; j < 10; j++) {
        var rndNumber = Math.floor(Math.random() * 10);
        if (rndNumber >= 7) {
            tempRndNumber.push(rndNumber);
        }
    }
    tempAllRndNumbers.push(tempRndNumber);
}

UPDATE: To achieve the desired output, make sure to loop through both arrays. Check out the solution here:

http://jsfiddle.net/jessikwa/1fbq0woo/

How come this 2-dimensional array is adding elements unexpectedly?

Answer №1

Answer №2

Answer №3

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