def rate_of_change(data, period):
catch_errors.check_for_period_error(data, period)<EOL>rocs = [((data[idx] - data[idx - (period - <NUM_LIT:1>)]) /<EOL>data[idx - (period - <NUM_LIT:1>)]) * <NUM_LIT:100> for idx in range(period - <NUM_LIT:1>, len(data))]<EOL>rocs = fill_for_noncomputable_vals(data, rocs)<EOL>return rocs<EOL>
Rate of Change.

Formula:
(Close - Close n periods ago) / (Close n periods ago) * 100