Follow

Keep Up to Date with the Most Important News

By pressing the Subscribe button, you confirm that you have read and are agreeing to our Privacy Policy and Terms of Use
Contact

How to extract certain Character from JS String

Given a String that represents a math operation , i want to extract the operations it contains , for ex : 5+4-3 will return two arrays : Operations = [+,-] and the operands will be [5,4,3]

// grab the input and so stuff when user finishes typing

const selectElement = document.querySelector('.formule');
selectElement.addEventListener('change', (event) => {
  const result = document.querySelector('.result');
  segmentFormule(event.target.value);
});


const segmentFormule = function (value){
// first separate operands from operations
    let myOperands = [];
    const formule = new String(value);
    
    // here i extracted the operands into an array, but i couldnt figure out how to extract the operations , so i just hardcoded Addition operation for now.
    
    myOperands=formule.split("+");
    
    let ColoredFormule = "";
    for (var i = 0 ; i < myOperands.length ; i++ ) {
        ColoredFormule += 
        '<span style="color:Red">'+myOperands[i]+'</span> '+'<span style="color:blue">+</span> ';
    }
    document.querySelector('.result').innerHTML = ColoredFormule;
    
    }
<label for="formuleField">Example input: 56+400+300</label>
</br>
<input type="text" class="formule" name="formuleField">
</br>
<div class="result"></div>

I Couldnt figure out how to extract the operations from the given input, any help is appreciated.

MEDevel.com: Open-source for Healthcare and Education

Collecting and validating open-source software for healthcare, education, enterprise, development, medical imaging, medical records, and digital pathology.

Visit Medevel

>Solution :

Use a regular expression to create two arrays using match. The first match will match against all none numbers, the second will match against all the numbers.

If you want integers in your operators array map over the array passing in Number for the callback.

const str = '5+4-36';
const operations = str.match(/[^\d]/g);
const operands = str.match(/\d+/g).map(Number);
console.log(operations, operands)
Add a comment

Leave a Reply

Keep Up to Date with the Most Important News

By pressing the Subscribe button, you confirm that you have read and are agreeing to our Privacy Policy and Terms of Use

Discover more from Dev solutions

Subscribe now to keep reading and get access to the full archive.

Continue reading