如何在哈希中为每个键添加前缀？

Question

我的哈希中有以下键:

address, postcode

我想为每个人添加"shipping_"前缀,以便它们成为:

shipping_address, shipping_postcode

代替.我怎样才能做到这一点？

Answer 1

hsh1 = {'address' => "foo", 'postcode' => "bar"}
hsh2 = Hash[hsh1.map{|k,v| [k.dup.prepend("shipping_"),v]}]
p hsh2
# >> {"shipping_address"=>"foo", "shipping_postcode"=>"bar"}

更新

hsh1 = {'address' => "foo", 'postcode' => "bar"}
hsh2 = Hash[hsh1.map{|k,v| ["shipping_#{k}",v]}]
p hsh2
# >> {"shipping_address"=>"foo", "shipping_postcode"=>"bar"}

Answer 2

在 Ruby >= 2.5 中，你可以这样做

hsh.transform_keys! {|k| 'shipping_' + k }
# => {"shipping_address"=>"foo", "shipping_postcode"=>"bar"} 

如果你想变得花哨

hsh.transform_keys! &'shipping_'.method(:+)
# => {"shipping_address"=>"foo", "shipping_postcode"=>"bar"}