Fastest way to find a String into an array of string

问题

The script has to verify if one predefined IP is present in a big array of IPs. Currently I code that function like this (saying that "ips" is my array of IP and "ip" is the predefined ip)

ips.each do |existsip|
  if ip == existsip
    puts "ip exists"
    return 1
  end
end
puts "ip doesn't exist"
return nil

Is there a faster way to do the same thing?

Edit : I might have wrongly expressed myself. I can do array.include? but what I'd like to know is : Is array.include? the method that will give me the fastest result?

回答1:

You can use Set. It is implemented on top of Hash and will be faster for big datasets - O(1).

require 'set'
s = Set.new ['1.1.1.1', '1.2.3.4']
# => #<Set: {"1.1.1.1", "1.2.3.4"}> 
s.include? '1.1.1.1'
# => true

回答2:

You could use the Array#include method to return you a true/false.

http://ruby-doc.org/core-1.9.3/Array.html#method-i-include-3F

if ips.include?(ip) #=> true
  puts 'ip exists'
else
  puts 'ip  doesn\'t exist'
end

回答3:

A faster way would be:

if ips.include?(ip)
  puts "ip exists"
  return 1
else
  puts "ip doesn't exist"
  return nil
end

回答4:

have you tried the Array#include? function?

http://ruby-doc.org/core-1.9.3/Array.html#method-i-include-3F

You can see from the source it does almost exactly the same thing, except natively.

回答5:

ips = ['10.10.10.10','10.10.10.11','10.10.10.12']

ip = '10.10.10.10'
ips.include?(ip) => true

ip = '10.10.10.13'
ips.include?(ip) => false

check Documentaion here

来源：https://stackoverflow.com/questions/9313957/fastest-way-to-find-a-string-into-an-array-of-string

标签

ruby

arrays

string

loops

comparison