Count IP addresses | 易学教程

问题

I stored the following IPs in an array:

10.2.3.1
10.2.3.5
10.2.3.10 - 10.2.3.15

I'm trying to count the total number of IP addresses. The total number of IP addresses should be 8. When I iterate through the array, I get a total of three counts. I need a way to count the third item:

10.2.3.10 - 10.2.3.15

Are there any IP address counters?

回答1:

If you need to convert an IP to a range, you'll need a function that converts an IPv4 value to an integer, then do math on those:

require 'ipaddr'

def ip(string)
  IPAddr.new(string).to_i
end

def parse_ip(string)
  string.split(/\s+\-\s+/).collect { |v| ip(v) }
end

def ip_range(string)
  ips = parse_ip(string)

  ips.last - ips.first + 1
end

ip_range("10.2.3.10 - 10.2.3.15")
# => 6

That should do it.

回答2:

It makes perfect sense to use the IPAddr class, as @tadman did, but it should be noted that the methods in that class are not doing anything very special. @tadman's answer works just fine if his method ip (the only one to use an IPAddr method) is replaced with:

def ip(str)
  str.split('.').map { |s| s.to_i.to_s(2).rjust(8,'0') }.join.to_i(2)
end

Let's compare:

require 'ipaddr'

def tadip(string)
  IPAddr.new(string).to_i
end

str = "10.2.3.10"
tadip str #=> 167904010 
ip    str #=> 167904010 

str = "255.255.255.255"
tadip str #=> 4294967295 
ip    str #=> 4294967295 

str = "172.0.254.1"
tadip str #=> 2885746177 
ip    str #=> 2885746177

In fact, ip, unlike IPAddr::new works for IPv6 (32**2 bits) as well as IPv4 (32 bits) IP's (-:

str = "172.0.254.1.22.33.44.55"
tadip str #=> IPAddr::InvalidAddressError: invalid address
ip    str #=> 12394185455143300151

来源：https://stackoverflow.com/questions/30650295/count-ip-addresses

标签

ruby

ip-address