# 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 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

Feeling lost in the world of random DSA topics, wasting time without progress? It's time for a change! Join our DSA course, where we'll guide you on an exciting journey to master DSA efficiently and on schedule.
Ready to dive in? Explore our Free Demo Content and join our DSA course, trusted by over 100,000 geeks!

Previous
Next