Creating a regular expression to capture a numerical value enclosed by different characters:

Question

Creating a regular expression to capture a numerical value enclosed by different characters:

export interface ValueParserResult {
  value: number, 
  error: string
}

interface subParseResult {
  result: (string | number) [], 
  error: string
}

class ValueParser {

  parse(eq: string, values: {[key: string] : number}, level?: number) : ValueParserResult {
    const result: ValueParserResult = { value: 0, error: "" }
  
    const numberRe: RegExp = /([^|\\(||/|/\\-|-|\\*|\\*\\-|+|\\^])+([0-9.]*)([$|(|)|/|/-|-|*|*-|+|])+/g;
          
    const eqParse = eq.split(" ").join('');
    eqParse.replace(numberRe, (matched) => {
      return " ," + matched;
    })
    
    console.log(eqParse)
    return result;

  }
}

const vp = new ValueParser();
const values = {x: 18, y:-3, z: 7}

const eq = "3452/132*67*(x+y/z)"

vp.parse(eq, values)

This snippet formats the eqParse data by adding a space and comma before each value instead of capturing surrounding strings.

javascript regex typescript

Answer 1

Answer №1

There seems to be some confusion here:

The pipe | is not functioning as an OR-operator within the [ ] class, and you cannot match a sequence of multiple characters (like /-) in that type of regex class. Each character inside the [ ] is treated individually, and the class matches only one of them.
The replace method does not alter the original string it operates on. Also, strings are immutable in JavaScript. Therefore, you need to store the result of this operation in a new variable.

Below is the corrected section of your code:

const eq = "123/456*82*(a+b/c)";
// A regex pattern that can match alphanumerics (including periods) or non-alphanumerics:
const numberRe = /[\w.]+|[^\w.]+/g
// Assign the return value of the replace call to eqParse:
const eqParse = eq.replace(/ /g, "").replace(numberRe, (matched) => {
  return ", " + matched; // Did you mean to add a comma first?
}).slice(2); // Skip the first ", "

console.log(eqParse);

Answer 2

There seems to be some confusion here:

The pipe | is not functioning as an OR-operator within the [ ] class, and you cannot match a sequence of multiple characters (like /-) in that type of regex class. Each character inside the [ ] is treated individually, and the class matches only one of them.
The replace method does not alter the original string it operates on. Also, strings are immutable in JavaScript. Therefore, you need to store the result of this operation in a new variable.

Below is the corrected section of your code:

const eq = "123/456*82*(a+b/c)";
// A regex pattern that can match alphanumerics (including periods) or non-alphanumerics:
const numberRe = /[\w.]+|[^\w.]+/g
// Assign the return value of the replace call to eqParse:
const eqParse = eq.replace(/ /g, "").replace(numberRe, (matched) => {
  return ", " + matched; // Did you mean to add a comma first?
}).slice(2); // Skip the first ", "

console.log(eqParse);

Answer 3

Answer №2

Updated regex pattern to extract numbers surrounded by other characters as shown below

const numberRe: RegExp = /(?<=[^\d.])\d+(?:\.\d+)?(?=[^\d.])/g;

I (geewhizbang) made a revision and shared it on a typescript playground:

Answer 4

Updated regex pattern to extract numbers surrounded by other characters as shown below

const numberRe: RegExp = /(?<=[^\d.])\d+(?:\.\d+)?(?=[^\d.])/g;

I (geewhizbang) made a revision and shared it on a typescript playground:

Creating a regular expression to capture a numerical value enclosed by different characters:

Answer №1

Answer №2

Similar questions

Is it possible to submit a form through a JavaScript hotkey?

Transfer data via ajax to the controller

Using a function from one class within another class by passing it as a prop

Storing files offline in Firefox 3.5 with file:// protocol

Accessing the observable's value by subscribing to it

Is there a way to implement a css/javascript property specifically for a div that is selected in the url?

Adding and adjusting the size of different DIV elements within a shared area

Is Jquery Mobile's Table lacking responsiveness?

In AngularJS, the execution of a subsequent AJAX call is reliant on the response of a preceding AJAX

Is it possible to save an entire webpage that infinitely scrolls without actually manually scrolling through it?

Transform a continuous string into an associative array with multiple dimensions

Firefox not clearing Highcharts points properly

Utilizing Javascript within a PHP while loop to showcase map markers

Adding elements to a JSON array in Javascript

Error encountered during Jasmine unit testing for the ng-redux @select directive

I am trying to figure out how to send a One Signal notification from my Ionic app using the One Signal REST API. I have reviewed the documentation, but I am still unable to understand it

Non-IIFE Modules

Is HTML-escaping necessary when implementing regex checks?

Leverage the power of Angular CLI within your current project

What is causing the sorting table to fail in React when using useState?