在 Ruby 中删除数组中的空位置

Question

I've created the following method:

def list_all_keys
$hash_table
keys=[]
output_file = File.open("output.txt", "w")
output_file.write("Hash Table: \n")
for i in 0..$hash_table.length - 1
  current_node = $hash_table[i]
  puts current_node.val
  while current_node.val != -1
    keys.push("key:" + current_node.key.to_s + ", value:" + current_node.val.to_s + ". pos:" + current_node.pos.to_s)
    current_node = current_node.next
  end
  puts "Hash:" + i.to_s + ", Entries:" + keys.to_s
  output_file.write("Hash:" + i.to_s + ", Entries:" + keys.to_s + "\n")
  keys = []
end
output_file.close
end
end

To write a file output.txt which would contain a hash map of all the values but my output includes a lot of empty positions (because of the while loop, I think).

Example of output:

Hash:3964, Entries:[]    /// CAN THESE BE PREVENTED? ///
Hash:3965, Entries:["key:quicker., value:1. pos:[3573]"]
Hash:3966, Entries:["key:easily, value:2. pos:[5639, 10510]"]
Hash:3967, Entries:["key:kept, value:6. pos:[1732, 1785, 3392, 5932, 7544, 9047]"]
Hash:3968, Entries:[]
Hash:3969, Entries:[]

Is there some way to prevent this?

Answer 1

Right before your puts "Hash" ... line you can write next if keys.empty?;

This will skip to the next iteration of the loop.

By the way, if you want to remove any nil elements of an array, you can use flatten .

Ie [nil, 2, 3, nil ].flatten will equal [2,3]