Deleting an element from a looped array in underscorejs

Question

Deleting an element from a looped array in underscorejs

Here is an example of an array:

var list = [5,10,15,20,25];

This code uses the forEach function in JavaScript to loop through the array:

list.forEach(function(item){
  console.log(item);
});

Now, if you want to remove certain items from the array while looping, for instance let's say you want to remove number 15, how can this be done?

javascript arrays underscore.js

Answer 1

Answer №1

Modifying an array while iterating over it can lead to unexpected results and errors. A better approach is to store the indexes that need to be modified in a separate array, then process them after the iteration is complete. Make sure to loop through this index array in reverse order to avoid dealing with changing indices.

Answer 2

Modifying an array while iterating over it can lead to unexpected results and errors. A better approach is to store the indexes that need to be modified in a separate array, then process them after the iteration is complete. Make sure to loop through this index array in reverse order to avoid dealing with changing indices.

Answer 3

Answer №2

Here are 2 different approaches, but I would suggest going with the first method.

const myArray = [10, 20, 30, 40, 50],
    itemsToRemove = [],
    index;

myArray.forEach((element, idx) => {
    if(element === 'something') {
        itemsToRemove.push(idx);
    }
});

while((index = itemsToRemove.pop()) !== null) {
    myArray.splice(index, 1);
}

// OR
for(index = myArray.length - 1; index >= 0; --index) {
    if(myArray[index] === 'something') {
        myArray.splice(index, 1);
    }
}

Answer 4

Here are 2 different approaches, but I would suggest going with the first method.

const myArray = [10, 20, 30, 40, 50],
    itemsToRemove = [],
    index;

myArray.forEach((element, idx) => {
    if(element === 'something') {
        itemsToRemove.push(idx);
    }
});

while((index = itemsToRemove.pop()) !== null) {
    myArray.splice(index, 1);
}

// OR
for(index = myArray.length - 1; index >= 0; --index) {
    if(myArray[index] === 'something') {
        myArray.splice(index, 1);
    }
}

Answer 5

Answer №3

To achieve this with underscores, you can follow these steps:

let numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];

let evenNumbers = _.filter(numbers, function(num){

    // Perform a task for each number - in this case, just logging the number
    console.log(num);

    // Only select even numbers
    return num % 2 == 0;

});

// Display the filtered list of even numbers
_.each(evenNumbers, function(num){
    console.log(num);
});

Answer 6

To achieve this with underscores, you can follow these steps:

let numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];

let evenNumbers = _.filter(numbers, function(num){

    // Perform a task for each number - in this case, just logging the number
    console.log(num);

    // Only select even numbers
    return num % 2 == 0;

});

// Display the filtered list of even numbers
_.each(evenNumbers, function(num){
    console.log(num);
});

Answer 7

Answer №4

Utilizing Underscore can significantly reduce the amount of code you need to write. This tool is truly a valuable resource.

var list = [10, 20, 30, 40, 50];
list = _.without(list, _.findWhere(list, {
  id: 3
}));
console.log(list);

Answer 8

Utilizing Underscore can significantly reduce the amount of code you need to write. This tool is truly a valuable resource.

var list = [10, 20, 30, 40, 50];
list = _.without(list, _.findWhere(list, {
  id: 3
}));
console.log(list);

Answer 9

Answer №5

Below is an efficient method I utilized to solve this issue by utilizing underscore's reject function:

_.each(_.reject(list, function(item) { return item === 10}), function(element){
  console.log(element);
});

Answer 10

Below is an efficient method I utilized to solve this issue by utilizing underscore's reject function:

_.each(_.reject(list, function(item) { return item === 10}), function(element){
  console.log(element);
});

Deleting an element from a looped array in underscorejs

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

Similar questions

Eliminate the legend color border

Transform your traditional sidebar into a sleek icon sidebar with Semantic UI

What is the best way to replace multiple strings with bold formatting in JavaScript without losing the previous bolded text?

Axios cancel token preemptively cancelling request before it is initiated

"Enhancements in Next.js 13: Optimizing static site generation with improved cache-control and index.txt management

Issues encountered when utilizing the each method to retrieve ajax data

Encountering Issues with Formatting InnerHtml Text using RegEx

Reset IntersectionObserverAPI to its initial state when none of the elements are in view

Retrieving information from a Rowdatapacket with expressjs

math symbols in brackets of python array that can be compared

Submitting form data in Angular is a straightforward process

Is the useNavigate() function failing to work consistently?

Having trouble passing data from router to View with EJS in Express. Despite trying, still encountering ReferenceError message

Retrieving Information from MongoDB Collection with Paginated Results in Universal Sorted Sequence

How can I recreate this image in 3D using three.js?

Is there a way for me to create a clickable link from a specific search result retrieved from a MySQL database using an AJAX

Choose the text value of the jQuery select menu from the specified column in the table

The JavaScript Top Slide Down effect is malfunctioning

Unable to pass value through form submission

Determine browser compatibility by evaluating the DOM Level