Determine if string is all caps with regular expression

Question

How can you determine if a string is all caps with a regular expression. It can include punctuation and numbers, just no lower case letters.

Answer 1

m/^[^a-z]*$/

For non-English characters,

m/^\P{Ll}*$/

(\P{Ll} is the same as [^\p{Ll}], which accepts all characters except the ones marked as lower-case.)