Regular expression for initials of name with dashes on it-CodePudding

I have been struggling with a regular expression to get the initials of a name with dashes.

For example, John Smith, I should get JS

The regular expressions I have is the following:

name.match(/(^\S\S?|\b\S)?/g).join("").match(/(^\S|\S$)?/g).join("").toUpperCase()

However, it does not pick the correct inital for the last name. For example:

John Andrew-Smith, I should get JA

However, I get JS.

Why does it pick up the letter after dash, I am a bit confused.

Any help is much appreciated

EDIT: Sorry forgot to add this part, I should ignore any middle name initials. For example, John Andrew Smith, should be JS, not JAS. As Andrew would be considered a middle name

If the last name has dash, then it is part of the lastname, so Andrew-Smith, would be the last name

CodePudding user response：

I would first split on spaces to get all initials in an array. Then join first and last elements from this array. So something like:

const allInitials = name.split(" ").map(n => n[0])
const initials = allInitials[0]   allInitials.splice(-1)

If you really want to use a regex, and do the above in one line you could do:

name.split(" ").map(n => n[0]).join("").replace(/^(.).*(.)$/g, "$1$2")

Silly me! The whole thing can just be:

name.replace(/^(.).*\s(.).*$/, "$1$2")

Basically, capture 1st initial, then greedy ignore all characters up to last whitespace character, then capture the next character, and then ignore all characters up to end of string

CodePudding user response：

I would use /(?<!-)[A-Z]/g

const names = [
  'John Smith',
  'John Andrew-Smith'
]

for (const name of names) {
  const initials = name.match(/(?<!-)[A-Z]/g).join('')
  console.log(name, initials)
}

CodePudding user response：

A more straightforward approach using regex would be:

match the first uppercase letter in a capture group ([A-Z])
then any other word characters \w
then a space \s
then another uppercase letter in a capture group ([A-Z])
and then any other word characters \w

^([A-Z])\w \s([A-Z])\w

Though as mentioned in the comments, regex is overkill for something like this.

var getInitials = function(name) {
  return name.match(/^([A-Z])\w \s([A-Z])\w /).splice(1, 2).join("");
}

console.log(getInitials("John Smith"));
console.log(getInitials("John Andrew-Smith"));

CodePudding user response：

You can try this:

const text = 'John Andrew Smith'
let result = /^(\S)\S /g.exec(text)[1]   /(\S)\S $/g.exec(text)[1];
document.write(result);

Because you said you don't want to match the middle name I decided to first match the first letter of the first word then concat it with the first letter of the last word.

/^(\S)\S /g : Matches the first letter of a word from the beginning.

/(\S)\S $/g : Matches the first letter of a word from the ending.