Javascript get number from string

Question

I have this an example:

const str = "Icecream, Milk, vanilla syrup, ice cubes20.0 SR180 calories"

I need a way to get the 20.0 from the string, it is always positioned before SR

I tried to convert the string to array like so:

const strArr = str.split(' ');

and try to get the index of the object contain SR

const index = strArr.map((object) => object).indexOf('SR');

But it showed me a result of -1

I was thinking to get the element by index - 1 to have the result of 20.0

Any other ideas, how to make it properly?

Thanks

Regex? str.match(/([\d\.]+) SR/)[1]

001
– 001

2022-07-28 18:09:19 +00:00
Commented Jul 28, 2022 at 18:09 — 001
– 001, Commented Jul 28, 2022 at 18:09
/(\d+(\.\d+)?) SR/

Hassan Imam
– Hassan Imam

2022-07-28 18:09:53 +00:00
Commented Jul 28, 2022 at 18:09 — Hassan Imam
– Hassan Imam, Commented Jul 28, 2022 at 18:09

IT goldman · Accepted Answer · 2022-07-28 18:14:26Z

2

If you're gonna split do it on SR. Then extract the digits from the end of the first string.

const str = "Icecream, Milk, vanilla syrup, ice cubes20.0 SR180 calories"
var arr = str.split("SR");
var rev = arr[0].trim().split("");
var num = []
while (rev.length) {
  var char = rev.pop();
  if (!(char >= '0' && char <= '9' || char == ".")) {
    break;
  }
  num.push(char);
}
var result = num.reverse().join("");
console.log(result)

answered Jul 28, 2022 at 18:14

IT goldman

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Comments

Dilli Chalise · Accepted Answer · 2022-07-28 19:49:50Z

1

I think this might help:

const finalNumber = str.split(' SR')[0].trim().split(' ').pop().replace(/[^\d.]/g, '');
console.log(finalNumber);

EDITED:

console.log("final", str.split('SR')[0].replace(/[^\d.]/g, '').split('.').slice(-2).join('.'))

edited Jul 28, 2022 at 19:49

answered Jul 28, 2022 at 18:40

Dilli Chalise

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3 Comments

IT goldman Over a year ago

Will fail if there are dots before the number "hello...12.0 SR"

Dilli Chalise Over a year ago

@ITgoldman Please go through updatd answer.

IT goldman Over a year ago

I'm afraid its still not perfect. There could be other numbers before the actual required number.

ulou · Accepted Answer · 2022-07-29 00:35:28Z

1

We can use match with following regexp:

const str = "Black coffee preparing with v60 filter18.00 SR38 Calories"
const res = str.match(/\d+(.\d+)?(?= SR)/g)
console.log(res[0])

Regexp explain:

\d+ - will match any string of digits,
(.\d+)? - will match floating point (optionally thanks to ?),
(?= SR) - will match a group after main expression without including it in results.

edited Jul 29, 2022 at 0:35

answered Jul 28, 2022 at 18:51

ulou

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2 Comments

zippax Over a year ago

Thank you for help, your code is work for most cases but it fails using this string: "Black coffee preparing with v60 filter18.0 SR38 Calories"

ulou Over a year ago

@zippax Fixed. I didn't have all your test cases.

Mrwaks · Accepted Answer · 2022-08-01 11:27:26Z

This should do the trick:

const getFilter = str => str.match(/ *\d+\.\d+(?= *SR)/).map(val => val.trim());

console.log(getFilter("Black coffee preparing with v60 filter18.00 SR38 Calories")); // ["18.00"]
console.log(getFilter("Black coffee preparing with v60 filter18.0 SR38 Calories")); // ["18.0"]
console.log(getFilter("Black coffee preparing with v60 filter 18.0SR38 Calories")); // ["18.0"]
console.log(getFilter("Black coffee preparing with v60 filter18.0 SR38 Calories")); // ["18.0"]
console.log(getFilter("Black coffee preparing with v60 filter18.0SR38 Calories")); // ["18.0"]
console.log(getFilter("Black coffee preparing with v60 filter200.001 SR38 Calories")); // ["200.001"]

I added security on any space, which will then need .trim()

In case the value can only be a decimal with two digits before the decimal point, you will have to use this regex instead:

/ *\d{2}\.\d+(?= *SR)/

The best would be for you to send us all possible cases, for a definitive regex...

Good luck !

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