红宝石 |数组积（）函数

Array#product() : product()是一个 Array 类方法，它返回所有数组中元素的所有组合的数组。

Syntax: Array.product()

Parameter: Array

Return: an array of all combinations of elements from all arrays.

示例 #1：

# Ruby code for product() method
  
# declaring array
a = [18, 22, 33, nil, 5, 6]
  
# declaring array
b = [1, 4, 1, 1, 88, 9]
  
# declaring array
c = [2, 5]
  
# product method example
puts "product() method form : #{a.product(c)}\n\n"
  
puts "product() method form : #{b.product(c)}\n\n"
  
puts "product() method form : #{c.product(a)}\n\n"

输出 ：

product() method form : [[18, 2], [18, 5], [22, 2], [22, 5], [33, 2], [33, 5], [nil, 2], [nil, 5], [5, 2], [5, 5], [6, 2], [6, 5]]

product() method form : [[1, 2], [1, 5], [4, 2], [4, 5], [1, 2], [1, 5], [1, 2], [1, 5], [88, 2], [88, 5], [9, 2], [9, 5]]

product() method form : [[2, 18], [2, 22], [2, 33], [2, nil], [2, 5], [2, 6], [5, 18], [5, 22], [5, 33], [5, nil], [5, 5], [5, 6]]

示例 #2：

# Ruby code for product() method
  
# declaring array
a = ["abc", "nil", "dog"]
  
# declaring array
c = [nil]
  
# declaring array
b = ["cow", nil, "dog"]
  
# product method example
puts "product() method form : #{a.product(c)}\n\n"
  
puts "product() method form : #{b.product(c)}\n\n"
  
puts "product() method form : #{c.product(a)}\n\n"

输出 ：

product() method form : [["abc", nil], ["nil", nil], ["dog", nil]]

product() method form : [["cow", nil], [nil, nil], ["dog", nil]]

product() method form : [[nil, "abc"], [nil, "nil"], [nil, "dog"]]