Python| C++ |从 IP 地址中删除前导零

给定一个 IP 地址，从 IP 地址中删除前导零。
例子：

Input : 100.020.003.400 
Output : 100.20.3.400

Input :001.200.001.004  
Output : 1.200.1.4

方法一：遍历加入

方法是用“.”分割给定的字符串。然后将其转换为删除前导零的整数，然后将它们连接回字符串。要将字符串转换为整数，我们可以使用 int(s)，然后通过 str(s) 将其转换回字符串，然后加入他们通过使用加入函数回来。

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 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))

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 integeres 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;
}

输出：

100.20.3.400
1.200.1.4

方法2：正则表达式

使用捕获组，匹配最后一个数字并复制它并防止所有数字被替换。
正则表达式 \d 可以解释为：

• \d ：匹配任何十进制数字

\d   Matches any decimal digit, this is equivalent
     to the set class [0-9].

• \b 允许您使用 \bword\b 形式的正则表达式执行“仅整个单词”搜索
  正则表达式 \b 可以解释为：
  

\b allows you to perform a "whole words only" search u
sing a regular expression in the form of \bword\b

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 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))

输出：

100.20.3.400
1.200.1.4