红宝石 |哈希选择（）方法

Hash#select() : select()是一个 Hash 类方法，它根据块条件从哈希中找到数组。

Syntax: Hash.select()

Parameter: Hash values
block condition

Return: array from the hash based on the block condition.

示例 #1：

# Ruby code for Hash.select() method
  
# declaring Hash value
a = { "a" => 100, "b" => 200 }
  
# declaring Hash value
b = {"a" => 100}
  
# declaring Hash value
c = {"a" => 100, "c" => 300, "b" => 200}
  
  
# select Value
puts "Hash a select form : #{a.select {|key, value| key < "b"}}\n\n"

输出 ：

Hash a select form : {"a"=>100}

示例 #2：

# Ruby code for Hash.select() method
  
# declaring Hash value
b = {"a" => 100}
  
# declaring Hash value
c = {"a" => 100, "c" => 300, "b" => 200}
  
  
# select Value
  
puts "Hash b select form : #{b.select{|key, value| value < 200}}\n\n"
  
puts "Hash c select form : #{c.select{|key, value| key < "b"}}\n\n"

输出 ：

Hash b select form : {"a"=>100}

Hash c select form : {"a"=>100}