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

问题描述

函数seq有什么区别?顺序?和科尔?

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

我发现一些信息分散在整个互联网上，但我认为最好将这些信息集中在这里.

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，如果它的参数实现了 ISeq 接口，则返回 true，也就是说它提供了方法first、rest、cons.请参阅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

sequential? 是一个谓词，如果它的参数实现了 Sequential 接口，则返回 true.Sequential 是一个标记接口(没有方法)，并且承诺可以按定义的顺序(例如列表，但不是地图)迭代集合.

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，如果其参数实现了 IPersistentCollection，则返回 true.例如，clojure 数据结构会返回 true，而原生 java 数据结构不会:

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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