Regex help

[Seh]

If I want to replace a text with remembering its case, is it possible like

Fir example, I have to replace hi with no and if text is Hi then new text will be No and if text is hI then new text will be nO

 

[paps93fr]

May be in two steps.

1) First step to know cases:
- everything in lower case: [a-z]{2}
- first letter in lower case and second in upper: [a-z][A-Z]
- first letter in upper case, second in lower: [A-Z][a-z]

Store each result in a Boolean

2) Second step:
Change the string accordingly to booleans