Search code examples
arraysrubydictionaryenumerator

Compare arrays in Ruby

I have an array of fully qualified domain names:

["filer1.abc.com", filer2.abc.com, filer3.xyz.com]

I have another array that has hostnames:

["filer1", "filer3"]

I have to compare the two arrays, and if the hostnames are present in fqdn, then I need to get the fqdn from the first array. For example, "filer1" is present in "filer1.abc.com", so I need to get the value "filer1.abc.com". And "filer3" is present in "filer3.xyz.com", so I need to get the value "filer3.xyz.com".

Help is appreciated.

["filer1.abc.com", filer2.abc.com, filer3.xyz.com].map.each_with_index {|vserver, indx| vserver.id.include? host_names[indx] unless host_names[indx].nil?}}

I get [true, nil, nil, nil], but I actually need the values of fqdn like ["filer1.abc.com"].

Solution 
  • fqdn_array = ["filer1.abc.com", "filer2.abc.com", "filer3.xyz.com"]
hostnames = ["filer1", "filer3"]

result = fqdn_array.keep_if{|fqdn| (hostnames - fqdn.split('.')).length < hostnames.length}
# => ["filer1.abc.com", "filer3.xyz.com"]

    Array#keep_if iterates through the array and keeps all elements where the block is true. In the block I split your fqdn at the dot into an array. Then I subtract it from the hostnames array. If the result is shorter than the original array length, I found a fqdn which includes one of your hostnames and the condition returns true.