ruby – 使用注入时可以分离出哈希的键和值吗？

在 ruby中的哈希函数中调用它们时,可以得到如下所示的键和值很好地分离：

{ :a => 1,:b => 2,:c => 3 }.each do |key,value| 
  puts "key is #{key} and value is #{value}"
end

=========================

key is :a and value is 1
key is :b and value is 2
key is :c and value is 3
=> {:a=>1,:b=>2,:c=>3}

但是,使用注入时似乎不起作用.

{ :a => 1,:c => 3 }.inject(0) do |result,key,value| 
  puts "key is #{key} and value is #{value}"
  result + value
end

=========================

key is [:a,1] and value is
TypeError: nil can't be coerced into Fixnum

在上面的简化示例中,我真的不需要键,所以我可以调用hash.values.inject,但是假设我需要这两个,那么有没有比这个可怕的风格更干净的方式呢？

{ :a => 1,key_and_value| 
  puts "key is #{key_and_value[0]} and value is #{key_and_value[1]}"
  result + key_and_value[1]
end

解决方法

看起来你需要：

{ :a => 1,(key,value)| 
    puts "key is #{key} and value is #{value}"
    result + value
end

原文地址：https://www.jb51.cc/ruby/265981.html