在两个大写字母之间插入空格？

Question

我将两个单词组合在一起，例如KitnerCoster并且我想在中间添加一个空格，如果将两个都大写的单词分开，那是唯一的区别KitnerCoster ？

Answer 1

Using regular expressions you could do something like

s/([a-z])([A-Z])/'$1 $2'/g

However my first trial to write a regular expression usually fails so you might have to correct one or the other part.

How do you want to handle a 1-character long word? Like 'X' in FooXBar? The X will not be recognized as a separate word by the above regular expression.

Answer 2

Do you care if the first word is capitalized? If not, do

// ASCII
preg_replace('/([a-z])([A-Z])/', '$1 $2', $string)
preg_replace('/([[:lower:]])([[:upper:]])/', '$1 $2', $string)

// Unicode (UTF-8)
preg_replace('/(\p{Ll})(\p{Lu})/u', '$1 $2', $string)

If you do care, and want to fix KitnerCostner but leave kitnerCostner alone, then do

// ASCII
preg_replace('/\b([A-Z]\S*[a-z])([A-Z])/', '$1 $2', $string)
preg_replace('/\b([[:upper:]]\S*[[:lower:]])([[:upper:]])/', '$1 $2', $string)

// Unicode (UTF-8)
preg_replace('/\b(\p{Lu}\S*\p{Ll})(\p{Lu})/u', '$1 $2', $string)

I've given versions that only match ASCII letters and ones that match all Unicode characters . The Unicode ones are available in PHP 5.1.0.