Whole Sequence Manipulations（针对整个序列的操作）

A handful of functions perform operations on a whole sequence (or sequences) at a time. These tend to be simpler than the other functions I’ve described so far. For instance, COPY-SEQ and REVERSE each take a single argument, a sequence, and each returns a new sequence of the same type. The sequence returned by COPY-SEQ contains the same elements as its argument while the sequence returned by REVERSE contains the same elements but in reverse order. Note that neither function copies the elements themselves—only the returned sequence is a new object.

有一些函数可以一次在整个序列（或多个序列）上进行操作。这些函数比目前为止我已描述的其他函数简单一些。例如，COPY-SEQ 和 REVERSE 都接受单一的序列参数并返回一个相同类型的新序列。COPY-SEQ 返回的序列包含与其参数相同的元素，而 REVERSE 返回的序列则含有顺序相反的相同元素。注意，这两个函数都不会复制元素本身，只有返回的序列是一个新对象。

The CONCATENATE function creates a new sequence containing the concatenation of any number of sequences. However, unlike REVERSE and COPY-SEQ, which simply return a sequence of the same type as their single argument, CONCATENATE must be told explicitly what kind of sequence to produce in case the arguments are of different types. Its first argument is a type descriptor, like the :element-type argument to MAKE-ARRAY. In this case, the type descriptors you’ll most likely use are the symbols VECTOR, LIST, or STRING. For example:

函数 CONCATENATE 创建一个将任意数量序列连接在一起的新序列。不过，跟 REVERSE 和 COPY-SEQ 简单地返回与其单一参数相同类型序列有所不同的是，CONCATENATE 必须被显式指定产生何种类型的序列，因为其参数可能是不同类型的。它的第一个参数是类型描述符，就像是 MAKE-ARRAY 的 :element-type 参数那样。这里最常用到的类型描述符是符号 VECTOR、LIST 和 STRING。 例如：

  1. (concatenate 'vector #(1 2 3) '(4 5 6))    ==> #(1 2 3 4 5 6)
  2. (concatenate 'list #(1 2 3) '(4 5 6))      ==> (1 2 3 4 5 6)
  3. (concatenate 'string "abc" '(#\d #\e #\f)) ==> "abcdef"