how to get the first numeric sequence in a string?

Question

The input variable contains one or more numeric strings in its character set, not having a fixed size and can have space between letters and numbers. In both cases, I need to identify only the first numerical sequence that appears in the string (it will never be separated by a space). Some examples of the input string:

"a12bcde097fg"  >> return 12
"120abc198672f" >> return 120
"a052bcd123fg"  >> return 052
"a 52 - bcd12"  >> return 52
"A b 123 cd 1"  >> return 123

Is there a way to do this with a single command and be effective in all situations?

Please [edit] your question to show what research you have done and any attempts you've made to solve the problem yourself. — Heretic Monkey, May 17 '21 at 18:02
In the meantime, some well-meaning people will post answers because this is a simple task and they can show off their prowess. Their answers do not serve the mission of Stack Overflow, which is to create a knowledge base of high-quality questions and answers. — Heretic Monkey, May 17 '21 at 18:05

score 3 · Answer 1 · answered May 17 '21 at 18:02

You could match only digits without global flag.

const 
    getFirstDigits = string => string.match(/\d+/)?.[0] || '',
    array = ["a12bcde097fg", "120abc198672f", "a052bcd123fg", "a 52 - bcd12", "A b 123 cd 1", "a"],
    result = array.map(getFirstDigits);

console.log(result);

score 1 · Answer 2 · answered May 17 '21 at 18:01

1

const s = "a12bcde097fg";
const r = /(\d+)/.exec(s);
if (r[0]) {
    console.log(r[0]); 
}

answered May 17 '21 at 18:01

jcollum

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how to get the first numeric sequence in a string?

2 Answers2