Print elements of array with strings and number with each element

April 26, 2023

Array contains number of elements. I need to print elements of array with strings and number with each element.

For example
Input

['1a', 'a', '2b', 'b']

Output should be
New array ['1a', '2b']

>Solution :

The easiest answer is, I think:

// the initial Array:
let input = ['1a', 'a', '2b', 'b'],
  // using Array.prototype.filter() to filter that initial Array,
  // retaining only those for whom the Arrow function returns
  // true (or truthy) values:
  result = input.filter(
    // the Arrow function passes a reference to the current
    // Array-element to the function body; in which we
    // use RegExp.test() to check if the current Array-element
    // ('entry') is matched by the regular expression:
    // /.../ : regular expression literal,
    // \d: matches a single number in base-10 (0-9),
    // [a-zA-Z]: matches a single character in the range
    // of a-z or A-Z (so lowercase or uppercase):
    (entry) => (/\d[a-zA-Z]/).test(entry));

console.log(result);

There are refinements, of course, such as:

`/^\d{1,2}[a-z]+$/i`,

/.../ regular expression literal,
^: the sequence starts at the beginning of the string,
\d{1,2}: a base-10 number character, which occurs a minimum of 1 time, and a maximum of 2 times (obviously the numbers can be amended to suit your specific needs),
[a-z]+: a character in the range of (lowercase) a-z, that occurs one or more times,
$: the end of the string,
i the i flag specifies a case-insensitive search.