How to split a CamelCase string in its substrings in Ruby?

Question

Dear Stackoverflow,

I have a nice CamelCase string such as ImageWideNice or ImageNarrowUgly. Now I want to break that string in its substrings, such as Image, Wide or Narrow, and Nice or Ugly.

I thought this could be solved simply by

camelCaseString =~ /(Image)((Wide)|(Narrow))((Nice)|(Ugly))/

But strangely, this will only fill $1 and $2, but not $3.

Do you have a better idea for splitting that string?

Answer 1

s = 'nowIsTheTime'

s.split /(?=[A-Z])/

=> ["now", "Is", "The", "Time"]

Answer 2

Have you tried

camelCaseString =~ /(Image)(Wide|Narrow)(Nice|Ugly)/

?

Answer 3

Event though this is a Ruby regex question and the answer by DigitalRoss is correct and shines by its simplicity, I want to add a Java answer:

// this regex doesn't work perfect with Java and other regex engines
"NowIsTheTime".split("(?=[A-Z])"); // ["", "Now", "Is", "The", "Time"]

// this regex works with first uppercase or lowercase characters
"NowIsTheTime".split("(?!(^|[a-z]|$))"); // ["Now", "Is", "The", "Time"]
"nowIsTheTime".split("(?!(^|[a-z]|$))"); // ["now", "Is", "The", "Time"]