How can i get the number and their unit?

Question

i want to create a regex to "- any number + unit" in a string
for example i have this string:
hello- world- 86 lo.  => 86 lo

in the -world- 6 lb   => 6 lb

and- the- dog -8kl     => 8kl

let data='in the world- 6 lo'

let  reg =  /-[0-9][a-z]/gi;
let matches = data.match(reg);
console.log(matches)

with his answer:


let data='in the world- 6 lo'

let  reg =  /-s*([0-9]+s*[a-z]+)/;
    let matches = data.match(reg);
    console.log(matches)

i get two answer
[
"- 6 lo",
"6 lo"
]
i want to get only the second => "6 lo"

The fourth bird · Accepted Answer

Match the hyphen and 0+ whitespace chars. The capture in group 1 matching 1+ digits, optional whitespace chars and 1 or more chars a-z.
A specific match with an optional decimal part, adding the units:
-s*([0-9]+(?:.d+)?(?:s*(?:l[ob]|kl))?)b

Regex demo


const regex = /-s*([0-9]+(?:.d+)?(?:s*(?:l[ob]|kl))?)b/g;
const str = `hello- world- 86 lo
in the -world- 6 lb
and- the- dog -8kl
hello- world- 86.6 lo
hello- world- 86`;

while ((m = regex.exec(str)) !== null) {
  console.log(m[1]);
}

Or a more broad match:
-s*([0-9]+(?:.d+)?(?:s*[a-z]+)?)b

Regex demo


const regex = /-s*([0-9]+(?:.d+)?(?:s*[a-z]+)?)b/g;
const str = `hello- world- 86 lo
in the -world- 6 lb
and- the- dog -8kl
hello- world- 86.6 lo
hello- world- 86`;
let m;

while ((m = regex.exec(str)) !== null) {
  console.log(m[1]);
}

Sascha · Answer

Make a match against the regexp and then map the result-array of this to get rid of the "- " at the beginning and return it.
In the regexp the minus had to be masked with , the spaces are optional, the unit accept all letters. If there are e.g. only max 2 letters wished than add {1,2}.
Because you wanted all results in the string (the g-parameter) I can't use the brackets in the regexp. So I had to map over the results and use here another regexp to get the desired part of the results.


function test(str) {
  let reg =  /- ?[0-9]+ ?[a-z]+/gi;
  let result = str.match(reg);
  return result.map(res => {
    return res.match(/- ?(.*)/)[1];
  });
}

console.log(test('hello- world- 86 lo, test-912 kg.'));
console.log(test('in the -world- 6 lb '));
console.log(test('and- the- dog -8kl'));

CRice · Answer

Well your data is a little odd, especially in the last case where it seems like the value might be negative. However, this regex should work for the cases you describe, and you can recombine the parts (sign, value, and unit) in whatever way you want afterward.


let data1 = 'in the world- 6 lo'
let data2 = 'in the -world- 6 lb'
let data3 = 'and- the- dog -8kl'

let  reg = /- ?(-|+)?(d+.?d*) ?(w+)/;

[data1, data2, data3].forEach(s => {
  console.log("Checking string:", s);
  const matches = s.match(reg);
  console.log("Sign:", matches[1] ?? "+");
  console.log("Value:", matches[2]);
  console.log("Unit:", matches[3]);
});

Note that I'd avoid using the global flag g since it prevents the .match method from returning the contents of each capture group.

Abdelrahman Hussien · Answer

let data='in the world- 6 lo'

let  reg =  /d+s?[A-Za-z]{2}/gi;
let matches = data.match(reg);
console.log(matches)

try this, you can replace [A-Za-z] with the only units you need.

How can i get the number and their unit?

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