The value accumulation clauses, on the other hand, provide a concise notation for a handful of common loop idioms having to do with accumulating values while looping. Each accumulation clause starts with a verb and follows this pattern:

The possible verbs are collect, append, nconc, count, , maximize, and minimize. Also available as synonyms are the present participle forms: collecting, appending, nconcing, counting, summing, maximizing, and minimizing.

The remaining accumulation clauses are used to accumulate numeric values. The verb count counts the number of times form is true, sum collects a running total of the values of form, maximize collects the largest value seen for form, and minimize collects the smallest. For instance, suppose you define a variable *random* that contains a list of random numbers.