Why does +/ % # 1 2 3 give me 0.333333 instead of the mean, 2?
You want +/ % # to be treated as a "fork", a 3-element sequence of verbs (called a train of verbs). Often that train is defined and named as follows.
mean =: +/ % # mean 1 2 3 2
To be recognized as a fork, the train of verbs must be isolated from surrounding elements in a way that the J sentence parser recognizes. Parentheses around the fork or other verb train is another way to isolate the train, as shown next.
(+/ % #) 1 2 3 2
See also the next question.
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