 GeeksforGeeks App
Open App Browser
Continue

# Python | C++ | Remove leading zeros from an IP address

Examples:

```Input : 100.020.003.400
Output : 100.20.3.400

Input :001.200.001.004
Output : 1.200.1.4```

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.

Implementation:

## C++

 `// Cpp program to remove leading zeros``// an IP address and print the IP`` ` `#include ``using` `namespace` `std;`` ` `// function to remove leading zeros``string removeZeros(string s)``{``    ``vector v;`` ` `    ``// splits the ip by "."``    ``for` `(``int` `i = 0; i < s.length(); i++) {``        ``string ans;``        ``while` `(i < s.length() && s[i] != ``'.'``) {``            ``ans += s[i];``            ``i++;``        ``}``        ``v.push_back(ans);``    ``}`` ` `    ``vector<``int``> num;``    ``// converts the words to integers to remove leading removeZeros``    ``for` `(``auto` `str : v) {``        ``int` `temp = 0;``        ``for` `(``int` `i = 0; i < str.length(); i++) {``            ``temp *= 10;``            ``temp += (str[i] - ``'0'``);``        ``}``        ``num.push_back(temp);``    ``}`` ` `    ``string ans = ``""``;``    ``// Convert back the integer to string and join them back to a string``    ``for` `(``auto` `i : num) {``        ``ans += ``'.'``;``        ``string temp;``        ``while` `(i) {``            ``temp += (``'0'` `+ (i % 10));``            ``i /= 10;``        ``}``        ``reverse(temp.begin(), temp.end());``        ``ans += temp;``    ``}`` ` `    ``return` `ans.substr(1);``}`` ` `int` `main()``{``    ``string ip;``    ``// example1``    ``ip = ``"100.020.003.400"``;``    ``cout << (removeZeros(ip)) << ``"\n"``;``    ``// example2``    ``ip = ``"001.200.001.004"``;``    ``cout << (removeZeros(ip)) << ``"\n"``;``    ``return` `0;``}`

## Python

 `# 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 integers 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```

Implementation:

## Python

 `# 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 integers 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```

Method 3: Storing the index of the first non zero character.

The approach is to split the string by “.” and store it in another string x.

Now get the index of the first non-zero character of that string and store

it in another variable ind. Initialise that variable to -1 which indicates that there is

no non-zero character in the string .In another variable append the substring picking

up characters from that index till the end in another string y.

Source code : c++ solution

## C++

 `#include``using` `namespace` `std;``int` `main()``{``   ``string s=``"152.02.0015.00"``;``   ``string newIPAdd(string);``   ``cout<

Output

`152.2.15.0`

My Personal Notes arrow_drop_up