associative operation

基本解释

This one is slightly more complicated but uses a Ruby hash (associative array) to simplify the reduction operation (see Listing 5).
虽然此应用程序稍微有些复杂，但是使用 Ruby hash（关联阵列）可简化 reduce 操作（请参考清单 5）。
The operation laws including:commutative law , associative law , cancellation law , unity of operation, inverse element, and distributive law between two operations, here we just omit them.
这些运算律包括：交换律，结合律，消去律，运算单位元，运算逆元，两个运算之间的分配律等，在此不再一一说明详细过程。
This idiom is an example of a mapping operation combined with a reduction or folding operation, whereby an associative operator (such as sum or max) is applied pairwise to a sequence of values.
该做法是与化简（reduce）或是折叠（fold）操作结合在一起的映射（map）操作的一个例子，某个关联的运算符（比如说sum或是max）凭此来成对地应用一系列的值。