Question

I have a sentence like:

Name: JOHN J. SMITH Sometag:

How would I grab the JOHN J SMITH part?

Sometag is not always the same so it would be more like get all all-capitalized words until one that is not.

UPDATE

"[A-Z. ]*" returns JOHN J. SMITH S
"[A-Z. ]*\b" returns nothing as well as
"\b[A-Z. ]*\b"

Answer 1

Try this

[A-Z. ]*\b

Let me know how it goes

You can be be more complete with this one

[\p{Lu}\p{M}\p{Z}\p{N}\p{P}\p{S}]*\b

But its a mouthful

Match a single character present in the list below «[\p{Lu}\p{M}\p{Z}\p{N}\p{P}\p{S}]*»
   Between zero and unlimited times, as many times as possible, giving back as needed (greedy) «*»
   A character with the Unicode property “uppercase letter” (an uppercase letter that has a lowercase variant) «\p{Lu}»
   A character with the Unicode property “mark” (a character intended to be combined with another character (e.g. accents, umlauts, enclosing boxes, etc.)) «\p{M}»
   A character with the Unicode property “separator” (any kind of whitespace or invisible separator) «\p{Z}»
   A character with the Unicode property “number” (any kind of numeric character in any script) «\p{N}»
   A character with the Unicode property “punctuation” (any kind of punctuation character) «\p{P}»
   A character with the Unicode property “symbol” (math symbols, currency signs, dingbats, box-drawing characters, etc.) «\p{S}»
Assert position at a word boundary «\b»

Or shorter

\P{Ll}*\b

Update 1

After your edit I would use this

Name: (\P{Ll}*)[ ]

The desired match will be in group 1. Note that I added a [ ] in the end so to signal a single space. You can convert this character class to a space if you want.

In C# this becomes

string resultString = null;
try {
    Regex regexObj = new Regex(@"Name: (\p{Ll}*)[ ]");
    resultString = regexObj.Match(subjectString).Groups[1].Value;
} catch (ArgumentException ex) {
    // Syntax error in the regular expression
}