looping through multidimensional array innermost loop

Question

I am ultimately trying to create a function that generates some html based on values in a two dimensional(?) array. However, I am struggling to loop through all of the values. In the following code, it is the bottom else clause that my program never enters:

let food = [
  [
    'Wedges',
    ['Hero Wedge', "Lettuce, tomato, yada", '$19.42'],
    ['Differebt Wedge', "Chicken, tomato, yada", '$12.42'],
  ],
  [
    'Chicken',
    ['Chicken', "Lettuce, tomato, yada", '$19.42'],
    ['Brocolli Wedge', "Chicken, tomato, yada", '$12.42'],
  ]
]
generate(food);

function generate(food){
  for(i = 0; i < food.length; i++){
    for(j = 0; j < food[i].length; j++){
      if(j === 0){
        sectionName = food[i][j]; // "Wedges"
      }
      else{
        for(y = 0; y < food[i][j]; y++){
          console.log("were in this statment"); //Never runs
        }
      }
    }
  }
}

When i = 0 and j = 1 doesn't food[i][j] = ['Hero Wedge', "Lettuce, tomato, yada", '$19.42'] ? And since this is an array with 3 elements y < food[i][j] should evaluate to true? Thanks in advance.

..... you have no idea how long I was trying to figure out what was wrong before coming to stackoverflow. But thanks! — Justin
– Justin, Commented Jun 6, 2019 at 13:00

Nina Scholz · Accepted Answer · 2019-06-06 13:04:43Z

You need to check the length of the array and declare all variables.

for(y = 0; y < food[i][j].length; y++){ // use length

A better approach by iteration from one instead of zero and without a check.

function generate(food) {
    var i, j, y, sectionName;
    for (i = 0; i < food.length; i++) {
        sectionName = food[i][0];                     // assign outside of the loop
        console.log('sectionName', sectionName);
        for (j = 1; j < food[i].length; j++) {        // start from one
            for (y = 0; y < food[i][j].length; y++) { // use length
                console.log(food[i][j][y]);
            }
        }
    }
}

let food = [['Wedges', ['Hero Wedge', "Lettuce, tomato, yada", '$19.42'], ['Different Wedge', "Chicken, tomato, yada", '$12.42']], ['Chicken', ['Chicken', "Lettuce, tomato, yada", '$19.42'], ['Brocolli Wedge', "Chicken, tomato, yada", '$12.42']]];

generate(food);

.as-console-wrapper { max-height: 100% !important; top: 0; }

Harshith Rai · Accepted Answer · 2019-06-06 13:07:02Z

0

The for loop is ranging from y = 0 to y being less than the element at food[i][j] instead of the length of food[i][j].

Where food[i][j] is "wedges"

So, basically, your for loop would translate to for(y = 0; y < "wedges"; y++){

Hence, replace food[i][j] in the for with food[i][j].length, making the loop as

else{
    for(y = 0; y < food[i][j].length; y++) { //take the length of food[i][j]
       console.log("were in this statement"); //Now runs
    }
}

This should solve your issue.

answered Jun 6, 2019 at 13:07

Harshith Rai

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