Looking for assistance with using an array in a for loop with an if-

Question

Looking for assistance with using an array in a for loop with an if-

I'm having trouble with a For loop array. I need to retrieve the data that is opposite of a given function, but when I use arr[i] != elem, it prints out the entire array. On the other hand, if I use arr[i] == elem, it gives me the array that I don't want. I still can't figure out why it's not working with != (not equal).

function getOppositeArray(arr, elem) {
let newArr = [];
// change code below this line
for(let i = arr.length -1; i >= 0 ; i--) {
  for(let j = arr[i].length-1;j >= 0;j--) {
    if(arr[i][j] !== elem) {
        newArr.push(arr[i]);
     }
   }
 }
 // change code above this line
  return newArr;
}

console.log(getOppositeArray([ ["trumpets", 2], ["flutes", 4], ["saxophones", 2] ], 2));

The desired result is ["flutes", 4]. I apologize if this question has been asked before. I have searched for an answer on Google but couldn't find one.

Thank you in advance for your assistance!

javascript arrays for-loop

Answer 1

Answer №1

Great effort, you were very close!

You had a good approach by checking each value in the array individually. For example: 2 !== "trumpets" and 2 !== 2. This caused all arrays to be pushed because they all contained a string value that would never match.

To improve your code, consider removing the second loop and explicitly checking for the second value of the inner array:

function filteredArray(arr, elem) {
let newArr = [];
// update code below this line
for(let i = arr.length -1; i >= 0 ; i--) {
    if(arr[i][1] !== elem) {
        newArr.push(arr[i]);
     }
 }
 // update code above this line
  return newArr;
}

console.log(filteredArray([ ["trumpets", 2], ["flutes", 4], ["saxophones", 2] ], 2));

The above snippet highlights the flaw in your current method but does not provide a very flexible function. To check if an array includes a specific value, it's best to utilize some of the built-in array methods:

function filteredArray(arr, elem) {
  return arr.filter(values => !values.includes(elem));
}

console.log(filteredArray([ ["trumpets", 2], ["flutes", 4], ["saxophones", 2] ], 2));

console.log(filteredArray([ ["amy", "beth", "sam"], ["dave", "sean", "peter"] ], "peter"));

Answer 2

Great effort, you were very close!

You had a good approach by checking each value in the array individually. For example: 2 !== "trumpets" and 2 !== 2. This caused all arrays to be pushed because they all contained a string value that would never match.

To improve your code, consider removing the second loop and explicitly checking for the second value of the inner array:

function filteredArray(arr, elem) {
let newArr = [];
// update code below this line
for(let i = arr.length -1; i >= 0 ; i--) {
    if(arr[i][1] !== elem) {
        newArr.push(arr[i]);
     }
 }
 // update code above this line
  return newArr;
}

console.log(filteredArray([ ["trumpets", 2], ["flutes", 4], ["saxophones", 2] ], 2));

The above snippet highlights the flaw in your current method but does not provide a very flexible function. To check if an array includes a specific value, it's best to utilize some of the built-in array methods:

function filteredArray(arr, elem) {
  return arr.filter(values => !values.includes(elem));
}

console.log(filteredArray([ ["trumpets", 2], ["flutes", 4], ["saxophones", 2] ], 2));

console.log(filteredArray([ ["amy", "beth", "sam"], ["dave", "sean", "peter"] ], "peter"));

Answer 3

Answer №2

function filteredArray(arr, elem) {
  var resultArray = arr.filter(function(item) {
    return item.indexOf(elem) == -1;
  });
  return resultArray[0]
}
console.log(
  filteredArray([["trumpets", 2], ["flutes", 4], ["saxophones", 2]], 2)
);
console.log(
  filteredArray([ ["amy", "beth", "sam"], ["dave", "sean", "peter"] ], "peter")
);

This function will fetch the first element in an array that does not match the provided parameter. To get all non-matching items, you can simply replace return resultArray[0] with return resultArray.

Let's consider an example:

filteredArray([["trumpets", 2], ["flutes", 4], ["saxophones", 5]], 2)

With return resultArray[0], the output will be ["flutes", 4]

But if we use return resultArray, it will return

[["flutes", 4], ["saxophones", 5]]

Answer 4

function filteredArray(arr, elem) {
  var resultArray = arr.filter(function(item) {
    return item.indexOf(elem) == -1;
  });
  return resultArray[0]
}
console.log(
  filteredArray([["trumpets", 2], ["flutes", 4], ["saxophones", 2]], 2)
);
console.log(
  filteredArray([ ["amy", "beth", "sam"], ["dave", "sean", "peter"] ], "peter")
);

This function will fetch the first element in an array that does not match the provided parameter. To get all non-matching items, you can simply replace return resultArray[0] with return resultArray.

Let's consider an example:

filteredArray([["trumpets", 2], ["flutes", 4], ["saxophones", 5]], 2)

With return resultArray[0], the output will be ["flutes", 4]

But if we use return resultArray, it will return

[["flutes", 4], ["saxophones", 5]]

Looking for assistance with using an array in a for loop with an if-

Answer №1

Answer №2

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