# Python | Remove leading zeros from an IP address

• Difficulty Level : Basic
• Last Updated : 29 Dec, 2020

Given an IP address, remove leading zeros from the IP address.

Examples:

```Input : 100.020.003.400
Output : 100.20.3.400

Input :001.200.001.004
Output : 1.200.1.4
```

## Recommended: Please solve it on “PRACTICE” first, before moving on to the solution.

Method 1 : Traversal and join

The approach is to split the given string by “.” and then convert it to an integer which removes the leading zeros and then join back them to a string.To convert a string to an integer we can use int(s) and then convert it back to string by str(s) and then join them back by using join function.

 `# Python program to remove leading zeros ``# an IP address and print the IP`` ` `# function to remove leading zeros``def` `removeZeros(ip):``     ` `    ``# splits the ip by "."``    ``# converts the words to integeres to remove leading removeZeros ``    ``# convert back the integer to string and join them back to a string``    ``new_ip ``=` `"."``.join([``str``(``int``(i)) ``for` `i ``in` `ip.split(``"."``)])  ``    ``return` `new_ip ;``     ` `     ` `# driver code   ``# example1``ip ``=``"100.020.003.400"`  `print``(removeZeros(ip))`` ` ` ` `# example2``ip ``=``"001.200.001.004"``print``(removeZeros(ip))`

Output:

```100.20.3.400
1.200.1.4
```

Method 2 : Regex

Using a capture group, match the last digit and copy it and prevents all the digits from being replaced.

regex \d can be explained as:

• \d : Matches any decimal digit
```\d   Matches any decimal digit, this is equivalent
to the set class [0-9].```
• \b allows you to perform a “whole words only” search using a regular expression in the form of \bword\b
regex \b can be explained as :
```\b allows you to perform a "whole words only" search u
sing a regular expression in the form of \bword\b```
 `# Python program to remove leading zeros ``# an IP address and print the IP using regex``import` `re `` ` `# function to remove leading zeros``def` `removeZeros(ip):``    ``new_ip ``=` `re.sub(r``'\b0+(\d)'``, r``'\1'``, ip)``    ``# splits the ip by "."``    ``# converts the words to integeres to remove leading removeZeros ``    ``# convert back the integer to string and join them back to a string``     ` `    ``return` `new_ip ``     ` `     ` `# driver code   ``# example1``ip ``=``"100.020.003.400"`  `print``(removeZeros(ip))`` ` ` ` `# example2``ip ``=``"001.200.001.004"``print``(removeZeros(ip))`

Output:

```100.20.3.400
1.200.1.4
```

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