Ruby Hash compact!() 函数

compact!() 是一个Hash类方法，它在删除Hash中所有的 “nil “值元素（如果有的话）后返回Hash。如果Hash中没有nil值，则返回nil值。

语法。Hash.compact!()

参数：要删除 “nil “值的哈希值。

返回：从哈希中删除所有的nil值。

nil – 如果哈希中没有nil值的话。

例子 #1 :

# Ruby code for compact!() method
# showing how to remove nil values
  
# declaring Hash value
a = {a:100, b:nil}
  
# declaring Hash value
b = {a:100, c:nil, b:200}
  
# declaring Hash value
c = {a:100}
  
  
# removing nil value from Hash
puts "removing nil value : #{a.compact!}\n\n"
  
# removing nil value from Hash
puts "removing nil value : #{b.compact!}\n\n"
  
# removing nil value from Hash
puts "removing nil value : #{c.compact!}\n\n"

输出:

removing nil value : {a:100}

removing nil value : {a:100, b:200}

removing nil value : {}

例子#2。

# Ruby code for compact!() method
# showing how to remove nil values
  
# declaring Hash value
a = { "a" => nil, "b" => 200 }
  
# declaring Hash value
b = {"a" => 100}
  
# declaring Hash value
c = {"a" => 100, "c" => nil, "b" => 200}
  
# removing nil value from Hash
puts "removing nil value : #{a.compact!}\n\n"
  
# removing nil value from Hash
puts "removing nil value : #{b.compact!}\n\n"
  
# removing nil value from Hash
puts "removing nil value : #{c.compact!}\n\n"

输出:

removing nil value : {b:200}

removing nil value : 

removing nil value : {a:100, b:200}