Regex match after delimiter and find higher number of the match?

Question

I have a match equation

 function start() { var str = "10x2+10x+10y100-20y30"; var match = str.match(/([az])=?(\\d+)/g);//find the higher value of power only and also print the power value only withput alphapets).i need match like "100" var text; if(match < 10) {text = "less 10";} else if(match == "10") {text == "equal";} else {text ="above 10";} document.getElementById('demo').innerHTML=text; } start(); 

 <p id="demo"></p> 

i need match the power values and also getting out with higher power value only.

example : 10x2+10y90+9x91 out --> "90" . what wrong with my and corret my regex match with suitable format.Thank You

Answer 1

The variable match contains all the powers that matches your regex, not just one. You'll have to iterate over them to find the greatest.

I took your code and modified it a bit to work :

 function start() { var str = "10x2+10x+10y100-20y30"; var match = str.match(/([az])=?(\\d+)/g);//find the higher value of power only and also print the power value only withput alphapets).i need match like "100" var max = 0; for (var i = 0; i < match.length; i++) { // Iterate over all matches var currentValue = parseInt(match[i].substring(1)); // Get the value of that match, without using the first letter if (currentValue > max) { max = currentValue; // Update maximum if it is greater than the old one } } document.getElementById('demo').innerHTML=max; } start(); 

 <p id="demo"></p> 

Answer 2

Try this:

 const str = '10x2+10x+10y100-20y30' ,regex = /([az])=?(\\d+)/g const matches = [] let match while ((match = regex.exec(str)) !== null) { matches.push(match[2]) } const result = matches.reduce((a, b) => Number(a) > Number(b) ? a : b) console.log(result)