红宝石 |哈希 keep_if()函数

Hash#keep_if()是一个 Hash 类方法，它只保留那些遵循块条件的键值对。

Syntax: Hash.keep_if()

Parameter: Hash values
block – condition

Return: key value pair that follows the block condition

示例 #1：

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

输出 ：

Hash a keep_if form : {:a=>100, :b=>200}

Hash b keep_if form : {:a=>100, :c=>300, :b=>200}

Hash c keep_if form : {:a=>100}

示例 #2：

# Ruby code for Hash.keep_if() 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}
  
# keep_if Value
puts "Hash a keep_if form : #{a.keep_if{|key| key != 100}}\n\n"
  
puts "Hash b keep_if form : #{b.keep_if{|key| key = 200}}\n\n"
  
puts "Hash c keep_if form : #{c.keep_if{|value| value != 200}}\n\n"

输出 ：

Hash a keep_if form : {"a"=>100, "b"=>200}

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

Hash c keep_if form : {"a"=>100, "c"=>300, "b"=>200}