How to extract first and last name from full name

Question

I have a regex that, given the full name, is supposed to capture the first and last name. It should exclude the suffix, like "Jr.":

(.+)\s(.+(?!\sJr\.))

But this regex applied against the string Larry Farry Barry Jones Jr. gives the match:

  1.    Larry Farry Barry Jones
  2.    Jr.

Why is my negative lookahead failing to ignore the "Jr." when parsing the full name? I want match #2 to contain "Jones".

The reason it does not give what you expect is because the second `.+` itself is `"Jr."`, which is not followed by (another) `"Jr."`. — sawa, Sep 26 '12 at 06:26
Be very careful assuming that names are "first" and "last". Many cultures don't follow that order. If you're assuming (naively) that you can split names and are going to use your assumed first name in a correspondence you could result in offending a customer or user. If you're dealing with a web form, put in separate fields for both. See http://stackoverflow.com/a/259694/128421 and http://www.kalzumeus.com/2010/06/17/falsehoods-programmers-believe-about-names/ — the Tin Man, May 10 '17 at 19:40

score 2 · Accepted Answer · answered Sep 26 '12 at 06:30

2

Rather than trying to do it with a single regex, I think the following would be a more maintainable code.

full_name = "Larry Farry Barry Jones Jr."
name_parts = full_name.split - ["Jr."]
first_name, last_name = name_parts[0], name_parts[-1]

answered Sep 26 '12 at 06:30

sawa

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score 1 · Answer 2 · answered Sep 26 '12 at 06:43

As a comment mentions it is the first .* that matches most of the string. The use of look ahead seems in correct here, as you do not want to return that value and do not need it to be included in a further match.

The following will split all words up but not return the 'Jr.' So you could take the first and last result.

(\w+\s)+?(?!\sJr\.)

I recommend Rubular for practicing Ruby RegExp.

score 1 · Answer 3 · answered Sep 26 '12 at 07:00

The reason is that your string is matched by your .+ till the end and then does the regex lookahead, there is no "Jr." following (because we are already at the end) ==> perfect, we match!!!

But that is because your pattern is wrong. Better would be this:

\S+(?:\s(?!Jr\.)\S+)*

See it here on Regexr

Means:

\S+ match a series of at least one non whitespace character.

(?:\s(?!Jr\.)\S+)* Non capturing group: Match a whitespace and then, if it is not "Jr.", match the next series of non whitespace characters. This complete group can be repeated 0 or more times.

How to extract first and last name from full name

3 Answers3