Question

items = ["pickle", "tuna", "pasta_sauce", "beans", "soup"]
price = [6, 5, 3, 2, 2]
items = price

我想打个电话，例如：pickle #=> 6; tuna # => 5，依此类推。

Answer 1

不可能动态创建局部变量。

您可以执行类似eval "abc = 123; puts abc"的操作，但此后abc仍未定义。

可以更改现有局部变量的值：

items = ["pickle", "tuna", "pasta_sauce", "beans", "soup"]
price = [6, 5, 3, 2, 2]

pickle = nil
tuna = nil
pasta_sauce = nil
beans = nil
soup = nil

local_binding = binding
items.zip(price).each do |var, val|
  local_binding.local_variable_set var, val
end

puts pasta_sauce
# outputs 3

您可能想做些不同的事情。例如，您可以动态创建实例变量：

items = ["pickle", "tuna", "pasta_sauce", "beans", "soup"]
price = [6, 5, 3, 2, 2]

items.zip(price).each do |var, val|
  instance_variable_set "@#{var}", val
end

puts @pasta_sauce
# outputs 3

Answer 2

您可能更适合将两个数组转换为哈希以进行访问，而不是使用元编程来设置变量（尽管@KimmoLehto提供了一个很好的答案，如果您选择该路线）。

作为创建两个数组的哈希的一种更简单的方法：

my_hash = Hash[items.zip(price)]
# or
my_hash = items.zip(price).to_h

items.zip(price)合并数组（请参阅：zip）：

[["pickle", 6], ["tuna", 5], ["pasta_sauce", 3], ["beans", 2], ["soup", 2]]

并使用Hash::[]或to_h转换为哈希：

{"pickle"=>6, "tuna"=>5, "pasta_sauce"=>3, "beans"=>2, "soup"=>2}

然后您可以使用标准哈希语法访问密钥：

my_hash['pickle'] # => 6

或如果希望使用.访问变量，则转换为和OpenStruct：

my_open_struct = OpenStruct.new(items.zip(price).to_h)
my_open_struct.pickle # => 6

希望有帮助。

Answer 3

您可以创建一个新的哈希来聚合这些数组。

<ContentWithTargetPath Include="references\libDependencies\linux64\libcvextern.so" Condition=" '$([System.Runtime.InteropServices.RuntimeInformation]::IsOSPlatform($([System.Runtime.InteropServices.OSPlatform]::Linux)))' ">
  <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
  <TargetPath>libcvextern.so</TargetPath>
</ContentWithTargetPath>


<ContentWithTargetPath Include="references\libDependencies\linux64\libSQLite.Interop.so" Condition=" '$([System.Runtime.InteropServices.RuntimeInformation]::IsOSPlatform($([System.Runtime.InteropServices.OSPlatform]::Linux)))' ">
  <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
  <TargetPath>libSQLite.Interop.so</TargetPath>
</ContentWithTargetPath>


<ContentWithTargetPath Include="references\libDependencies\win64\cvextern.dll" Condition=" '$(OS)' == 'Windows_NT' ">
  <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
  <TargetPath>cvextern.dll</TargetPath>
</ContentWithTargetPath>

如何组合2个数组并将元素设置为变量？

3 个答案: