我从一个空数组和一个键值哈希开始。
我想迭代哈希并将其与空数组进行比较。如果数组中尚不存在每个 k,v 对的值,我想使用该值创建一个对象,然后访问一个对象方法将键附加到对象内的数组中。
这是我的代码
class Test
def initialize(name)
@name = name
@values = []
end
attr_accessor :name
def values=(value)
@values << value
end
def add(value)
@values.push(value)
end
end
l = []
n = {'server_1': 'cluster_x', 'server_2': 'cluster_y', 'server_3': 'cluster_z', 'server_4': 'cluster_x', 'server_5': 'cluster_y'}
n.each do |key, value|
l.any? do |a|
if a.name == value
a.add(key)
else
t = Test.new(value)
t.add(key)
l << t
end
end
end
p l
我希望看到这个:
[
#<Test:0x007ff8d10cd3a8 @name=:cluster_x, @values=["server_1, server_4"]>,
#<Test:0x007ff8d10cd2e0 @name=:cluster_y, @values=["server_2, server_5"]>,
#<Test:0x007ff8d10cd1f0 @name=:cluster_z, @values=["server_3"]>
]
相反,我只是得到一个空数组。
我认为不满足条件if a.name == value
,然后不调用 add 方法。
@Cyzanfar给了我一个关于要寻找什么的线索,我在这里找到了答案
https://stackoverflow.com/a/34904864/5006720
n.each do |key, value|
found = l.detect {|e| e.name == value}
if found
found.add(key)
else
t = Test.new(value)
t.add(key)
l << t
end
end
@ARL你快到了!您需要考虑的最后一件事是found
何时实际返回一个对象,因为detect
会在某个时候找到一个匹配的对象。
n.each do |key, value|
found = l.detect {|e| e.name == value}
if found
found.add(key)
else
t = Test.new(value)
t.add(key)
l << t
end
end
您实际上只想在返回found
时添加Test
的新实例nil
。此代码应生成所需的输出:
[
#<Test:0x007ff8d10cd3a8 @name=:cluster_x, @values=["server_1, server_4"]>,
#<Test:0x007ff8d10cd2e0 @name=:cluster_y, @values=["server_2, server_5"]>,
#<Test:0x007ff8d10cd1f0 @name=:cluster_z, @values=["server_3"]>
]
我在你的代码中观察到两件事:
def values=(value)
@values << value
def add(value)
@values.push(value)
- 两种方法做同样的事情,推动一个值,因为
<<
是一种句法糖意味着推动 - 您更改了
values=
的含义,这通常是为二传手方法保留的,相当于attire_writer :values
。
为了说明在 Ruby 中有很多方法可以做事,我提出以下建议:
class Test
def initialize(name, value)
@name = name
@values = [value]
end
def add(value)
@values << value
end
end
h_cluster = {} # intermediate hash whose key is the cluster name
n = {'server_1': 'cluster_x', 'server_2': 'cluster_y', 'server_3': 'cluster_z',
'server_4': 'cluster_x', 'server_5': 'cluster_y'}
n.each do | server, cluster |
puts "server=#{server}, cluster=#{cluster}"
cluster_found = h_cluster[cluster] # does the key exist ? => nil or Test
# instance with servers list
puts "cluster_found=#{cluster_found.inspect}"
if cluster_found
then # add server to existing cluster
cluster_found.add(server)
else # create a new cluster
h_cluster[cluster] = Test.new(cluster, server)
end
end
p h_cluster.collect { | cluster, servers | servers }
执行:
$ ruby -w t.rb
server=server_1, cluster=cluster_x
cluster_found=nil
server=server_2, cluster=cluster_y
cluster_found=nil
server=server_3, cluster=cluster_z
cluster_found=nil
server=server_4, cluster=cluster_x
cluster_found=#<Test:0x007fa7a619ae10 @name="cluster_x", @values=[:server_1]>
server=server_5, cluster=cluster_y
cluster_found=#<Test:0x007fa7a619ac58 @name="cluster_y", @values=[:server_2]>
[#<Test:0x007fa7a619ae10 @name="cluster_x", @values=[:server_1, :server_4]>,
#<Test:0x007fa7a619ac58 @name="cluster_y", @values=[:server_2, :server_5]>,
#<Test:0x007fa7a619aac8 @name="cluster_z", @values=[:server_3]>]