We can treat a string variable itself as an array as follows.
S$="ONE" ... S$[0]=="O", S$[1]=="N", S$[2]=="E"
Multiple dimension arrays are also available as follows.
DIM S$[3]:S$[0]="ZERO":S$[1]="ONE":S$[2]="TWO"
... S$[1][0]=="O", S$[1][1]=="N", S$[2][1]=="W" ...
Could you confirm them yourself?
0そうだね 未プレイ