The assign command allows you to assign to variables Xi generated by concatenation. That is, X is a variable, i is a non-negative integer, and we are assigning A to Xi. If two arguments are given then any assignment to the variable Xi is cleared.
# generate 5 variables and assign xi = i^2 for (i=0; i < 5; i=i+1) assign(x,i,i^2); x0; x1; x2; x3; x4; 0 1 4 9 16 # clear the assignments for (i=0; i < 5; i=i+1) assign(x,i); x0; x1; x2; x3; x4; x0 x1 x2 x3 x4