In Intellij, how do I toggle between camel case and underscore spaced?

Solution 1:

Two plugins offer this feature:

I use a plugin called String Manipulation which does what you need (and more).

Select historyOfPresentIllness and press Alt / option+M to bring up the plugin menu, then press:

• 5 - To snake_case (or to camelCase) which converts to history_of_present_illness
• 6 - To hyphen-case (or to snake_case) which converts to history-of-present-illness

To make this easier, you could set up a shortcut at File | Settings | Keymap.

SHIFT+Alt / option+U toggles the selection between formats:

historyOfPresentIllness --> history_of_present_illness --> HISTORY_OF_PRESENT_ILLNESS --> HistoryOfPresentIllness --> historyOfPresentIllness

You can also undo your changes (now that a bug in the plugin got fixed).

Solution 2:

Very simple press Clr + F to open Find/Replace panel and check [✓] Regex copy past regex

Find: [_]{1,1}([a-z])

Replace: \U$1

Press [Replace all] button, Enjoy

Thanks @piotrek for _some_awe_var to _someAweVar

Use Find: (\w)[_]{1,1}([a-z])
Replace: $1\U$2