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