4
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clojure.core/seq
([coll])
Returns a seq on the collection. If the collection is
empty, returns nil. (seq nil) returns nil. seq also works on
Strings, native Java arrays (of reference types) and any objects
that implement Iterable.
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clojure.core/seq?
([x])
Return true if x implements ISeq
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顯然是空的?基於seq。空有什麼區別?而且無?我很困惑。seq和seq有什麼區別?
clojure.core/empty?
([coll])
Returns true if coll has no items - same as (not (seq coll)).
Please use the idiom (seq x) rather than (not (empty? x))
多:
(not (seq?())) ;;false
(not (seq())) ;;true
(not nil) ;;true