顺序函数seq？有什么区别？和科尔？ [英] What is the difference between the functions seq?, sequential? and coll?

问题描述

seq函数之间有什么区别？顺序的？和coll？

What is the difference between the functions seq? sequential? and coll?

我发现一些信息散布在整个互联网上，但是我认为最好在此处集中这些信息。

I found some information scattered throughout the internet, but I think it would be better to centralize that information here.

推荐答案

seq？是一个谓词，如果其参数实现 ISeq 接口，也就是说它提供了 first ， rest ，方法缺点。请参见 http://clojure.org/sequences 。

seq? is a predicate that returns true if it's argument implements ISeq interface, which is to say it provides the methods first,rest,cons. See http://clojure.org/sequences.

(seq? [1 2])
false
(seq? (seq [1 2]))
true

顺序？是一个谓词，如果其参数实现 Sequential 接口，则返回true。 Sequential 是一个标记接口（无方法），并保证可以按定义的顺序（例如列表，但不映射）对集合进行迭代。

sequential? is a predicate that returns true if it's argument implements Sequential interface. Sequential is a marker interface (no methods) and is a promise that the collection can be iterated over in a defined order (e.g. a list, but not a map).

(sequential? [])
true
(sequential? {})
false

coll？是一个谓词，如果其返回值是true参数实现 IPersistentCollection 。因此，例如clojure数据结构将返回true，而本机java数据结构将不会：

coll? is a predicate that returns true if its argument implments IPersistentCollection. So for example the clojure data structures would return true, whereas native java data structures would not:

(coll? {:a 1})
true
(coll? (java.util.HashMap.))
false

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