Let's say I have a numbers spread throughout a page:
Lorem ipsum dolor sit amet, {5} consectetur adipisicing elit {2},
sed do eiusmod {9} tempor incididunt ut labore et dolore magna aliqua.
Luckily, they are wrapped in curly brackets {}. Using javascript — jQuery is not available —, how do I add these number to return the total: 16 in this case.
You can use eval here...
var str = 'Lorem , {5} elit {2}, sed {9} tempor';
var sum = eval(str.match(/\d+(?=\})/g).join('+'));
/* returned value: (Number)
16
*/
eval is generally a bad idea, this is a reasonable use of it, especially since the input has gone through sanitisation by only allowing digits.
+ and evaling it
Try this:
var str = 'Lorem ipsum dolor sit amet, {5} consectetur adipisicing elit {2}, sed do eiusmod {9} tempor incididunt ut labore et dolore magna aliqua.';
var result = str.match(/\{[^}]+\}/g).join('').match(/\d+/g).reduce(function(a,b) {
return +a + +b;
});
console.log(result); //=>16
Edit: Check the gmatch helper if you want to make it a bit clearer: http://jsbin.com/asufek/1/edit
Array.prototype.reduce is not avaiable in older browsers.
match doesn't capture groups with g flag that's why the two regex./\d+(?=\})/g which works fine.This is a solution that demonstrates getting the text from the page using Node.textContent, matching a floating point number (this includes whole integers) with exponent (if exists) surrounded in "{" and "}" but not consuming the trailing "}", using a regex, and then performing a sum of them . During the sum we remove the leading "{" by using String slice.
HTML
<div>Lorem ipsum<span>dolor sit amet, </span>{5} consectetur adipisicing<span>elit {2}, sed do eiusmod</span><span>{9} tempor incididunt ut labore </span>et dolore magna aliqua.</div>
Javascript
var array = document.body.textContent.match(/{[-+]?\d*\.?\d+([eE][-+]?\d+)?(?=\})/g);
var length = array.length;
var i = 0;
var sum = 0;
while (i < length) {
sum += parseFloat(array[i].slice(1));
i += 1;
}
console.log(sum);
On jsfiddle
For interest sake, here is a jsperf of the current (3) answers.
