I may be dumb for not knowing how to do this, but I can't figure out the code for making a character repeat its animation while holding down a key, and instantly stopping to the idle animation when not holding the key.

What the idle and walking animation looks like for more information:

switch costume to [idlenormal v]
wait (6) secs
repeat (2)
next costume
wait (2) secs
end

switch costume to [walk1 v]
repeat (3)
wait (0.25) secs
next costume
end
wait (0.25) secs

I've figured out how to construct this system. I'd show how to do it, however, it is quite lengthy.

I've got it!

when green flag clicked
forever
if <key (any v) pressed?> then
set [idle action v] to [false]
if <(walk action)=[false]> then
stop [other scripts in sprite v]
broadcast [walk action v]
set [walk action v] to [true]
end
else
set [walk action v] to [false]
if <(idle action)=[false]> then
stop [other scripts in sprite v]
broadcast [idle action v]
set [idle action v] to [true]
end
end
end
when I receive [idle action v]
switch costume to [idle normal v]
wait (6) secs
repeat (2)
next costume
wait (2) secs
end
set [idle action v] to [false]
when I receive [walk action v]
switch costume to [walk1 v]
repeat (3)
wait (0.25) secs
next costume
end
wait (0.25) secs
set [walk action v] to [false]

I haven't tested this, let me know if you have any bugs!