How to find sum of integers in a string using JavaScript

问题

I created a function with a regular expression and then iterated over the array by adding the previous total to the next index in the array.

My code isn't working. Is my logic off? Ignore the syntax

function sumofArr(arr) { // here i create a function that has one argument called arr
  var total = 0; // I initialize a variable and set it equal to 0 
  var str = "12sf0as9d" // this is the string where I want to add only integers
  var patrn = \\D; // this is the regular expression that removes the letters
  var tot = str.split(patrn) // here i add split the string and store it into an array with my pattern
  arr.forEach(function(tot) { // I use a forEach loop to iterate over the array 
    total += tot; // add the previous total to the new total
  }
  return total; // return the total once finished
}

回答1:

var patrn = \\D; // this is the regular expression that removes the letters

This is not a valid regular expression in JavaScript.

You are also missing a closing bracket in the end of your code.

A simpler solution would be to find all integers in the string, to convert them into numbers (e.g. using the + operator) and summing them up (e.g. using a reduce operation).

var str = "12sf0as9d";
var pattern = /\d+/g;
var total = str.match(pattern).reduce(function(prev, num) {
  return prev + +num;
}, 0);

console.log(str.match(pattern)); // ["12", "0", "9"]
console.log(total);              // 21

回答2:

you have some errors :

change var patrn = \\D with var patrn = "\\D"

use parseInt : total += parseInt(tot);

function sumofArr(arr){ // here i create a function that has one argument called arr
var total = 0; // I initialize a variable and set it equal to 0 
var str = "12sf0as9d" // this is the string where I want to add only integers
var patrn = "\\D"; // this is the regular expression that removes the letters
var tot = str.split(patrn) // here i add split the string and store it into an array with my pattern

arr.forEach(function(tot){ // I use a forEach loop to iterate over the array 
total += parseInt(tot); // add the previous total to the new total
})
return total; // return the total once finished
}

alert(sumofArr(["1", "2", "3"]));

https://jsfiddle.net/efrow9zs/

回答3:

function sumofArr(str) {
 var tot = str.replace(/\D/g,'').split('');
   return  tot.reduce(function(prev, next) {
   return parseInt(prev, 10) + parseInt(next, 10);
});}

sumofArr("12sf0as9d");

来源：https://stackoverflow.com/questions/39236731/how-to-find-sum-of-integers-in-a-string-using-javascript

标签

javascript

expression

sum-of-digits