For a string of the formats: abc_def_ghl or abcd_xyz, abc_def_ghl_k, etc

I like to replace the "_char" with the uppercased char, for example:

abc_def_ghl --> abcDefGhl

abcd_xyz --> abcdXyz

abc_def_ghl_k --> abcDefGhlK

etc.

What is the RegExp for it?


Thanks