Ruby Hash 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。

语法。Hash.keep_if()

参数：哈希值

block – condition

返回：遵循区块条件的键值对

例子 #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}

例子 #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}