Using a RegEx to match IP addresses in Python

Question

I m trying to make a test for checking whether a sys argv input matches the RegEx for an IP address     As a simple test  I have the following     import re  pat   re compile   d 1 3   d 1 3   d 1 3   d 1 3    test   pat match hostIP  if test     print  Acceptable ip address  else     print  Unacceptable ip address    However when I pass random values into it  it returns  Acceptable IP address  in most cases  except when I have an  address  that is basically equivalent to  d

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I came across the same situation  I found the answer with use of socket library helpful but it doesn t provide support for ipv6 addresses  Found a better way for it   Unfortunately it Works for python3 only  import ipaddress  def valid ip address       try           print ipaddress ip address address          return True     except          return False  print valid ip  10 10 20 30   print valid ip  2001 DB8  1   print valid ip  gibberish

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import re  st1    This is my IP Address10 123 56 25 789 356 441 561 127 255 123 55 192 168 1 2 3 192 168 2 2 str1    Here my valid IP Address is only 192 168 2 2 and assuming 10 123 56 25 is not a  valid one as it is combined with some string and 192 168 1 2 3 not valid   pat   r  s   25 0-5  2 0-4  0-9   01   0-9   0-9      3   25 0-5  2 0-4  0-9   01   0-9   0-9   s       match   re search pat st1   print match group                     RESTART  C  Python27 Srujan re practice py                  192 168 2 2    This will grep the exact IP Address  we can ignore any pattern look like an IP Address but not a valid one  Ex   Address10 123 56 25    789 356 441 561   192 168 1 2 3     Please comment if any modifications are required

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You have to modify your regex in the following way  pat   re compile    d 1 3    d 1 3    d 1 3    d 1 3       that s because   is a wildcard that stands for  every character

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IP address uses following authentication     255  ---  250-255 249  ---  200-249 199  ---  100-199 99   ---  10-99  9    ---  1-9  import re     k   0 while k  lt  5        i   input   nEnter Ip address          ip   re match     1  0-9  0-9     2  5  0-5     2  0-4  0-9     1  0-9  0-9     0-9  0-9     0-9     1  0-9  0-9    2  5  0-5    2  0-4  0-9    1  0-9  0-9    0-9  0-9    0-9     1  0-9  0-9    2  5  0-5    2  0-4  0-9    1  0-9  0-9    0-9  0-9    0-9     1  0-9  0-9   2  5  0-5   2  0-4  0-9   1  0-9  0-9   0-9  0-9   0-9     i      k   k   1      if ip          print    n                                print   Valid IP address           print                                   break     else           print    nInvalid IP   else       print    nAllowed Max 5 times      Reply me if you have doubt

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This works for python 2 7   import re a raw input  Enter a valid IP Address    b    0-9           3   if re match b a  and b lt 255      print  Valid  else      print  invalid

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You are trying to use   as a   not as the wildcard for any character   Use    instead to indicate a period

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import re ipv raw input  Enter an ip address   a ipv split      s str bin int a 0    bin int a 1    bin int a 2    bin int a 3     s s replace  0b       m re search     0 1  1 8    0 1  1 8    0 1  1 8    0 1  1 8    s  if m is not None      print  Valid sequence of input  else       print  Invalid input sequence    Just to keep it simple I have used this approach  Simple as in to explain how really ipv4 address is evaluated  Checking whether its a binary number is although not required  Hope you like this

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If you really want to use RegExs  the following code may filter the non-valid ip addresses in a file  no matter the organiqation of the file  one or more per line  even if there are more text  concept itself of RegExs      def getIps filename       ips          with open filename  as file          for line in file              ipFound   re compile    d 1 3    d 1 3    d 1 3    d 1 3     findall line              hasIncorrectBytes   False             try                      for ipAddr in ipFound                          for byte in ipAddr                              if int byte  not in range 1  255                                   hasIncorrectBytes   True                                 break                             else                                  pass                     if not hasIncorrectBytes                          ips append ipAddr              except                  hasIncorrectBytes   True      return ips

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def ipcheck      1 Validate the ip adderess input ip   input  Enter the ip    flag   0  pattern      d 1 3   d 1 3   d 1 3   d 1 3    match   re match pattern  input ip  if  match       field   input ip split          for i in range 0  len field            if  int field i    lt  256               flag    1         else              flag   0 if  flag    4       print  valid ip   else      print  No match for ip or not a valid ip

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str    255 255 255 255  print str split        list1   str split       condition 0  if len list1   4      for i in list1          if int i  gt  0 and int i  lt  255              condition condition 1  if condition  4      print  Given number is not IP address   else      print  Given number is valid IP address

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quot  quot  quot  regex for finding valid ip address  quot  quot  quot  import re   IPV4   re fullmatch    0-2  0-5  2   d 2   d    0-2  0-5  2   d 2   d    0-2  0-5  2   d 2   d    0-2  0-5  2   d 2   d     100 1 1 2    if IPV4      print   quot Valid IP address quot    else      print  quot Invalid IP address quot

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regex for ip v4       25 0-5  2 0-4  0-9   01   0-9  0-9        3  25 0-5  2 0-4  0-9   01   0-9  0-9       otherwise you take not valid ip address like 999 999 999 999  256 0 0 0 etc

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Using regex to validate IP address is a bad idea - this will pass 999 999 999 999 as valid  Try this approach using socket instead - much better validation and just as easy  if not easier to do   import socket  def valid ip address       try           socket inet aton address          return True     except          return False  print valid ip  10 10 20 30   print valid ip  999 10 20 30   print valid ip  gibberish     If you really want to use parse-the-host approach instead  this code will do it exactly   def valid ip address       try          host bytes   address split              valid    int b  for b in host bytes          valid    b for b in valid if b  gt   0 and b lt  255          return len host bytes     4 and len valid     4     except          return False

[python] Using a RegEx to match IP addresses in Python

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