{$["j";x in V]'[x;"_"]} / Case

[kdb_newbie]

https://learninghub.kx.com/forums/topic/jx-in-vx_-case

https://code.kx.com/q/learn/reading/strings/#c_ns_n_nts

{$[“j”;x in V]'[x;“_”]} / Case

May I ask how does each both work here please?

[roryk]

As the comment says, this is case, https://code.kx.com/q/ref/maps/#case