[英]How to merge two arrays of hashes by the same pair of key and value ruby
我是红宝石的新手。 我有两个哈希:
f = { "server"=>[{ "hostname"=>"a1", "ip"=>"10" }, {"hostname"=>"b1", "ip"=>"10.1" }] }
g = { "admin" =>[{ "name"=>"adam", "mail"=>"any", "hostname"=>"a1" },
{ "name"=>"mike", "mail"=>"id", "hostname"=>"b1"}]}
我想得到另一个像这样的哈希:
{ "data" => [{"hostname"=>"a1", "ip"=>"10", "name" =>"adam", "mail"=>"any"},
{"hostname"=>"b1", "ip"=>"10.1", "name" =>"mike", "mail"=>"id"}]}
对"hostname"=>"something"
总是匹配两个数组的哈希值。 我试过这样的事情:
data = server.merge(admin)
但它并不容易,因为你认为它不起作用。 你能帮我合并这些哈希并解释你未来的表现吗?
我现在能想到的一种快速方式如下:
servers = { "server" => [{"hostname"=>"a1", "ip"=>"10"}, {"hostname"=>"b1", "ip"=>"10.1"}]}
admins = { "data" => [{"hostname"=>"a1", "ip"=>"10", "name" =>"adam", "mail"=>"any"}, {"hostname"=>"b1", "ip"=>"10.1", "name" =>"mike", "mail"=>"id"}]}
# FYI: you can just use arrays for representing the above data, you don't necessarily need a hash.
list_of_entries = (servers.values + admins.values).flatten
grouped_by_hostname_entries = list_of_entries.group_by { |h| h['hostname'] }
grouped_by_hostname_entries.map { |_, values| values.inject({}, :merge) }
#=> [{"hostname"=>"a1", "ip"=>"10", "name"=>"adam", "mail"=>"any"}, {"hostname"=>"b1", "ip"=>"10.1", "name"=>"mike", "mail"=>"id"}]
代码和示例
ff = f["server"].each_with_object({}) { |g,h| h[g["hostname"]] = g }
#=> {"a1"=>{"hostname"=>"a1", "ip"=>"10"}, "b1"=>{"hostname"=>"b1", "ip"=>"10.1"}}
{ "data"=>g["admin"].map { |h| h.merge(ff[h["hostname"]]) } }
#=> {"data"=>[{"name"=>"adam", "mail"=>"any", "hostname"=>"a1", "ip"=>"10"},
# {"name"=>"mike", "mail"=>"id", "hostname"=>"b1", "ip"=>"10.1"}]}
说明
我们想要产生一个哈希
{ "data"=>arr }
哪里
arr #=> [{ "name"=>"adam", "mail"=>"any", "hostname"=>"a1", "ip"=>"10" },
# { "name"=>"mike", "mail"=>"id", "hostname"=>"b1", "ip"=>"10.1" }]
所以我们只需要计算arr
。
首先,我们创建哈希
ff = f["server"].each_with_object({}) { |g,h| h[g["hostname"]] = g }
#=> {"a1"=>{"hostname"=>"a1", "ip"=>"10"}, "b1"=>{"hostname"=>"b1", "ip"=>"10.1"}}
我们有
enum = f["server"].each_with_object({})
#=> #<Enumerator: [{"hostname"=>"a1", "ip"=>"10"},
# {"hostname"=>"b1", "ip"=>"10.1"}]:each_with_object({})>
我们可以通过将它转换为数组来查看由此枚举器生成的元素(并传递给它的块):
enum.to_a
#=> [[{"hostname"=>"a1", "ip"=>"10"}, {}],
# [{"hostname"=>"b1", "ip"=>"10.1"}, {}]]
注意
enum.each { |g,h| h[g["hostname"]] = g }
#=> {"a1"=>{"hostname"=>"a1", "ip"=>"10"},
# "b1"=>{"hostname"=>"b1", "ip"=>"10.1"}}
each
传递enum
的第一个元素并使用并行分配 (也称为多个赋值 ) 分配块变量:
g,h = enum.next
#=> [{"hostname"=>"a1", "ip"=>"10"}, {}]
g #=> {"hostname"=>"a1", "ip"=>"10"}
h #=> {}
我们现在可以执行块计算:
h[g["hostname"]] = g
#=> h["a1"] = {"hostname"=>"a1", "ip"=>"10"}
#=> {"hostname"=>"a1", "ip"=>"10"}
返回值是块变量h
的新值。 然后将enum
的第二个元素传递给块并执行块计算:
g,h = enum.next
#=> [{"hostname"=>"b1", "ip"=>"10.1"}, {"a1"=>{"hostname"=>"a1", "ip"=>"10"}}]
g #=> {"hostname"=>"b1", "ip"=>"10.1"}
h #=> {"a1"=>{"hostname"=>"a1", "ip"=>"10"}}
请注意,哈希h
已更新。
h[g["hostname"]] = g
#=> {"hostname"=>"b1", "ip"=>"10.1"}
所以现在
h #=> {"a1"=>{"hostname"=>"a1", "ip"=>"10"},
# "b1"=>{"hostname"=>"b1", "ip"=>"10.1"}}
和
ff #=> {"a1"=>{"hostname"=>"a1", "ip"=>"10"}, "b1"=>{"hostname"=>"b1", "ip"=>"10.1"}}
现在我们可以计算arr
:
g["admin"].map { |h| h.merge(ff[h["hostname"]]) }
g [“admin”]的第一个元素被传递给块并分配给块变量:
h = g["admin"][0]
#=> {"name"=>"adam", "mail"=>"any", "hostname"=>"a1"}
并执行块计算:
h.merge(ff[h["hostname"]])
#=> h.merge(ff["a1"])
#=> h.merge({"hostname"=>"a1", "ip"=>"10"})
#=> {"name"=>"adam", "mail"=>"any", "hostname"=>"a1", "ip"=>"10"}
然后
h = g["admin"][1]
#=> {"name"=>"mike", "mail"=>"id", "hostname"=>"b1"}
h.merge(ff[h["hostname"]])
#=> h.merge(ff["b1"])
#=> h.merge({"hostname"=>"a2", "ip"=>"10"})
#=> {"name"=>"mike", "mail"=>"id", "hostname"=>"a2", "ip"=>"10"}
因此,
arr
#=> [{"name"=>"adam", "mail"=>"any", "hostname"=>"a1", "ip"=>"10"},
#=> {"name"=>"mike", "mail"=>"id", "hostname"=>"b1", "ip"=>"10.1"}]
块返回,我们完成了。
作为另一种变体,你可以试试这个
h1 = { "server" => [{"hostname"=>"a1", "ip"=>"10"}, {"hostname"=>"b1", "ip"=>"10.1"}]}
h2 = { "admin" => [{"name" =>"adam", "mail"=>"any", "hostname"=>"a1"}, {"name" =>"mike", "mail"=>"id", "hostname"=>"b1"}]}
h1['server'].zip(h2['admin']).map { |ar| ar.first.merge(ar.last) }
#=> [{"hostname"=>"a1", "ip"=>"10", "name"=>"adam", "mail"=>"any"}, {"hostname"=>"b1", "ip"=>"10.1", "name"=>"mike", "mail"=>"id"}]
zip
让我们同时遍历两个或更多数组。
我们用map
来返回结果。
在map
块ar
将等于
[{"hostname"=>"a1", "ip"=>"10"}, {"name"=>"adam", "mail"=>"any", "hostname"=>"a1"}]
[{"hostname"=>"b1", "ip"=>"10.1"}, {"name"=>"mike", "mail"=>"id", "hostname"=>"b1"}]
所以ar.first
将是{"hostname"=>"a1", "ip"=>"10"}
,而ar.last
将是{"name"=>"adam", "mail"=>"any", "hostname"=>"a1"}
最后我们使用merge
来组合两个哈希。
希望这会有所帮助。
f = { "server"=>[{ "hostname"=>"a1", "ip"=>"10" },
{"hostname"=>"b1", "ip"=>"10.1" }] }
g = { "admin" =>[{ "name"=>"adam", "mail"=>"any", "hostname"=>"a1" },
{ "name"=>"mike", "mail"=>"id", "hostname"=>"b1"}]}
# manual way
host_admin_merge = []
host_admin_merge << f["server"].first.merge(g["admin"].first)
host_admin_merge << f["server"].last.merge(g["admin"].last)
# a bit more automated, iterate, test key's value, append to new array
host_admin_merge = []
f["server"].each do |host|
g["admin"].each do |admin|
if admin[:hostname] == host[:hostname]
host_admin_merge << host.merge(admin)
end
end
end
# assign the array to a hash with "data" as the key
host_admin_hash = {}
host_admin_hash["data"] = host_admin_merge
p host_admin_hash
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.