Swap out an element in a list that does not correspond to any element in a separate list with a designated value

Question

Swap out an element in a list that does not correspond to any element in a separate list with a designated value

I am fairly new to Javascript and currently struggling with looping through an array and replacing items. I hope my explanation is clear.

Here is the initial array:

[
  '1:1',   'blah',
  '1:2',   undefined,
  '1:3',   'smith',
  '1:4',   'blah',
  '1:5',   'williams',
  '1:6',   'blah',
  '1:7',   'blah'
]

and here is another array:

[ 
   'taylor', 
   'smith', 
   'williams', 
   'brown'
]

The goal is to replace any value in the first array that does not follow the format of /([0-9]+):([0-9]+)/g and is not found in the second array. Therefore, all occurrences of "blah" and "undefined" in the first array should be replaced with johnson. Any names that match the second array as well as the #:# numbers should remain unchanged. The desired output is:

[
  '1:1',   'johnson',
  '1:2',   'johnson',
  '1:3',   'smith',
  '1:4',   'johnson',
  '1:5',   'williams',
  '1:6',   'johnson',
  '1:7',   'johnson',
]

javascript arrays replace

Answer 1

Answer №1

To achieve the desired outcome, we can incorporate a straightforward if statement within a for loop.

var originalArray = [
  '1:1',   'blah',
  '1:2',   undefined,
  '1:3',   'smith',
  '1:4',   'blah',
  '1:5',   'williams',
  '1:6',   'blah',
  '1:7',   'blah'
];

var matchArray = [ 
   'taylor', 
   'smith', 
   'williams', 
   'brown'
];

for (var i = 0; i < originalArray.length; i++) {
    var value = originalArray[i];
    //Verify if it conforms to your RegEx
    if (value !== undefined) {
      var doesItMatchRegEx = value.match(/([0-9]+):([0-9]+)/g);
    } else {
      originalArray[i] = "johnson";
    }
    //Check its presence in the second array
    var isItInSecondArray = matchArray.includes(value);
    if (!doesItMatchRegEx && !isItInSecondArray) {
        //Replace with Johnson if mismatched
        originalArray[i] = "johnson";
    }
}

console.log(originalArray);

Answer 2

To achieve the desired outcome, we can incorporate a straightforward if statement within a for loop.

var originalArray = [
  '1:1',   'blah',
  '1:2',   undefined,
  '1:3',   'smith',
  '1:4',   'blah',
  '1:5',   'williams',
  '1:6',   'blah',
  '1:7',   'blah'
];

var matchArray = [ 
   'taylor', 
   'smith', 
   'williams', 
   'brown'
];

for (var i = 0; i < originalArray.length; i++) {
    var value = originalArray[i];
    //Verify if it conforms to your RegEx
    if (value !== undefined) {
      var doesItMatchRegEx = value.match(/([0-9]+):([0-9]+)/g);
    } else {
      originalArray[i] = "johnson";
    }
    //Check its presence in the second array
    var isItInSecondArray = matchArray.includes(value);
    if (!doesItMatchRegEx && !isItInSecondArray) {
        //Replace with Johnson if mismatched
        originalArray[i] = "johnson";
    }
}

console.log(originalArray);

Answer 3

Answer №2

To simplify things, let's denote the primary array as arr, and the array of names as names. The following code snippet can help achieve the desired outcome:

arr.map(item => !/([0-9]+):([0-9]+)/g.test(item) && !names.includes(item) ? 'johnson' : item)

Answer 4

To simplify things, let's denote the primary array as arr, and the array of names as names. The following code snippet can help achieve the desired outcome:

arr.map(item => !/([0-9]+):([0-9]+)/g.test(item) && !names.includes(item) ? 'johnson' : item)

Answer 5

Answer №3

In my opinion, for the task at hand, utilizing the map() function of the array in a functional manner would be highly effective. Another option to consider could be using filter(), but since the goal is to replace specific entries, map() achieves it with greater efficiency.

With the Array.prototype.map() method, a specified function is executed on each element of the array, and the result of that function is stored at the corresponding index in the new array that is returned.

validNames = ['taylor'...];
numberFormatRegex = /([0-9]+):([0-9]+)/g;

// The following function will be applied to each item in the array; the output of the function becomes the new value in the mapped array
mapFunction = (value) => {
  if(!validNames.includes(value) && !numberFormatRegex.test(value)){
    // Only values NOT present in the validNames list AND failing the regex test will follow this condition
    
    return 'Johnson';
  }
  // This code block executes only if the previous return statement did not trigger, thus applying to valid values

}

// Invoke the map() method with our designated function and store the result in a new array
// It's important to note that the original inputArray remains unchanged, while the modified array is assigned to newArray
newArray = inputArray.map(mapFunction);

Answer 6

In my opinion, for the task at hand, utilizing the map() function of the array in a functional manner would be highly effective. Another option to consider could be using filter(), but since the goal is to replace specific entries, map() achieves it with greater efficiency.

With the Array.prototype.map() method, a specified function is executed on each element of the array, and the result of that function is stored at the corresponding index in the new array that is returned.

validNames = ['taylor'...];
numberFormatRegex = /([0-9]+):([0-9]+)/g;

// The following function will be applied to each item in the array; the output of the function becomes the new value in the mapped array
mapFunction = (value) => {
  if(!validNames.includes(value) && !numberFormatRegex.test(value)){
    // Only values NOT present in the validNames list AND failing the regex test will follow this condition
    
    return 'Johnson';
  }
  // This code block executes only if the previous return statement did not trigger, thus applying to valid values

}

// Invoke the map() method with our designated function and store the result in a new array
// It's important to note that the original inputArray remains unchanged, while the modified array is assigned to newArray
newArray = inputArray.map(mapFunction);

Swap out an element in a list that does not correspond to any element in a separate list with a designated value

Answer №1

Answer №2

Answer №3

Similar questions

The function Server.listeners is not recognized by the system

Locate the absent date within a php array

Exploring two data points within a two-dimensional array

Make sure to wait until the fetch function is finished before triggering another action

Displaying a sub-menu for specific menu options to fetch content using routes in ReactJS

Expressjs Error- ReferenceError: cors has not been defined in this context

What is the process for integrating a custom script prior to building in a react application?

cPanel is incompatible with node version 12.16.0

How should you proceed when npm install cannot locate a specific dependency, even though you can easily download it manually?

Every 5 seconds, a message of "true" is sent. If the request does not reach the server within 10 seconds, how can a function be triggered?

Can someone assist me with navigating through my SQL database?

Simple JavaScript timer with loop and pause

Guide to executing two child processes sequentially in Node JS

Switch button - reveal/conceal details

Generate an HTML document from a website page

Unable to access variables beyond the function scope results in an undefined value

How to use jQuery to highlight the parent element when clicking on a child element?

What is the best way to incorporate a 'category filter' in Angular2?

Setting configuration files in Node.js with npm configuration

I am encountering an issue with Angular where the following error message is displayed: "src/app/app.component.html:18:20 - error TS2339: Property 'DepScreen' does not exist on type 'AppComponent'"