Given a string S, the task is to move all the digits present in the string, to the beginning of the string.
Examples:
Input: S = “Geeks4forGeeks123”
Output: 4123neveropen
Explanation:
The given string contains digits 4, 1, 2, and 3. Moving all the digits to the beginning of the string modifies the string to “4123neveropen”.Input: S = “neveropen1234 A Com56puter Science Port7al”
Output: 1234567neveropen A Computer Science Portal
Approach: The idea is to traverse the string and maintain two strings, one string contains the digits and another string contains non-numeric characters. In the end, append both the strings to the result in the required order.
Below is the implementation of the above approach:
C++
// CPP program for the above approach#include <bits/stdc++.h>using namespace std;// Function to move all the digit// to the beginning of the stringvoid moveAllDigitAtBeginning( string str){ // Calculate the string length int len = str.size(); // Stores the digits string digits = ""; // Stores the non-numeric character string nonNumericCharacter = ""; // Traverse the string and // check if there is a digit for (int i = 0; i < str.size(); i++) { char c = str[i]; // If character is a digit, // add it to the string digits if (c >= 48 && c <= 57) { digits += c; } // Otherwise, add it to the // string nonNumericCharacter else { nonNumericCharacter += c; } } // Append both the strings digits += nonNumericCharacter; // Print the string cout << digits << endl;}// Driver Codeint main(){ // Given String str string str = "neveropen123"; moveAllDigitAtBeginning(str); return 0;}// this code is contributed by harimahecha |
Java
// Java program for the above approachclass GFG { // Function to move all the digit // to the beginning of the string static void moveAllDigitAtBeginning( String str) { // Calculate the string length int len = str.length(); // Stores the digits StringBuilder digits = new StringBuilder(); // Stores the non-numeric character StringBuilder nonNumericCharacter = new StringBuilder(); // Traverse the string and // check if there is a digit for (char c : str.toCharArray()) { // If character is a digit, // add it to the string digits if (c >= 48 && c <= 57) { digits.append(c); } // Otherwise, add it to the // string nonNumericCharacter else { nonNumericCharacter.append(c); } } // Append both the strings digits.append( nonNumericCharacter.toString()); // Print the string System.out.print( digits.toString() + " "); } // Driver Code public static void main(String args[]) { // Given String str String str = "neveropen123"; moveAllDigitAtBeginning(str); }} |
Python3
# Python program for the above approach# Function to move all the digit# to the beginning of the stringdef moveAllDigitAtBeginning(str): # Calculate the string length Len=len(str) # Stores the digits digits="" # Stores the non-numeric character nonNumericCharacter="" # Traverse the string and # check if there is a digit for i in range(len(str)): c=str[i] # If character is a digit, # add it to the string digits if(ord(c)>=48 and ord(c)<=57): digits+=c # Otherwise, add it to the # string nonNumericCharacter else: nonNumericCharacter+=c # Append both the strings digits+=nonNumericCharacter # Print the string print(digits) # Driver Code# Given String strstr="neveropen123"moveAllDigitAtBeginning(str)# This code is contributed by Aman Kumar |
C#
// C# program for the above approachusing System;public class GFG{// Function to move all the digit// to the beginning of the stringstatic void moveAllDigitAtBeginning(string str){// Calculate the string lengthint len = str.Length;// Stores the digitsstring digits = "";// Stores the non-numeric characterstring nonNumericCharacter = "";// Traverse the string and// check if there is a digitfor (int i = 0; i < str.Length; i++){ char c = str[i]; // If character is a digit, // add it to the string digits if (c >= 48 && c <= 57) { digits += c; } // Otherwise, add it to the // string nonNumericCharacter else { nonNumericCharacter += c; }}// Append both the stringsdigits += nonNumericCharacter;// Print the stringConsole.WriteLine(digits);}// Driver Codestatic public void Main (){// Given String strstring str = "neveropen123";moveAllDigitAtBeginning(str);}}// this code is contributed by Pushpesh Raj. |
Javascript
<script>// JavaScript program for the above approach// Function to move all the digit// to the beginning of the stringfunction moveAllDigitAtBeginning(str){ // Calculate the string length var len = str.length; // Stores the digits var digits = []; // Stores the non-numeric character var nonNumericCharacter = []; // Traverse the string and // check if there is a digit var temp = str.split(""); for(const c of temp) { // If character is a digit, // add it to the string digits if (c.charCodeAt(0) >= 48 && c.charCodeAt(0) <= 57) { digits.push(c); } // Otherwise, add it to the // string nonNumericCharacter else { nonNumericCharacter.push(c); } } // Append both the strings digits.push(nonNumericCharacter.join("")); // Print the string document.write(digits.join("") + " ");}// Driver Code// Given String strvar str = "neveropen123";moveAllDigitAtBeginning(str);// This code is contributed by rdtank</script> |
Output:
123neveropen
Time Complexity: O(N)
Auxiliary Space: O(1)
Regular Expression based Approach: The given problem can also be solved using Regular Expression and replace all non-numeric characters with the empty string (“ “) that give you all numbers and replace all digits with the empty string (“ “) that gives you all non-numeric characters. In the end, concatenate the string and print the result.
Below is the implementation of the above approach:
C++
// C++ program for the above approach#include <iostream>#include <string>#include <regex>using namespace std;// Function to move all the digit// at the beginning of the stringvoid moveAllDigitAtBeginning(string str) { // Replace all the non-numeric // characters with " " and // replace all digits with " " string moveAllDigit = regex_replace(str, regex("\\D+"), "") + regex_replace(str, regex("\\d"), ""); // Print the string cout << moveAllDigit; } // Driver Code int main() { // Given String str string str = "neveropen1234"; moveAllDigitAtBeginning(str); return 0; }// This code is contributed by akashish__ |
Java
// Java program for the above approachclass GFG { // Function to move all the digit // at the beginning of the string static void moveAllDigitAtBeginning( String str) { // Replace all the non-numeric // characters with " " and // replace all digits with " " String moveAllDigit = str.replaceAll("\\D+", "") + str.replaceAll("\\d+", ""); // Print the string System.out.println(moveAllDigit); } // Driver Code public static void main(String args[]) { // Given String str String str = "neveropen1234"; moveAllDigitAtBeginning(str); }} |
Python3
import re# Function to move all the digit# at the beginning of the stringdef moveAllDigitAtBeginning(str): # Replace all the non-numeric # characters with "" and # replace all digits with "" moveAllDigit = re.sub(r'\D+',"", str) + re.sub(r'\d+',"", str) # Print the string print(moveAllDigit)# Driver Codeif __name__ == "__main__": # Given String str str = "neveropen1234" moveAllDigitAtBeginning(str) # This code is contributed by divyansh2212 |
C#
// C# program for the above approachusing System;using System.Text.RegularExpressions;public class GFG { // Function to move all the digit // at the beginning of the string static void moveAllDigitAtBeginning( String str) { // Replace all the non-numeric // characters with " " and // replace all digits with " " String moveAllDigit = Regex.Replace(str, "\\D+", "") +Regex.Replace(str, "\\d", ""); // Print the string Console.WriteLine(moveAllDigit); } // Driver Code public static void Main(String []args) { // Given String str String str = "neveropen1234"; moveAllDigitAtBeginning(str); }}// This code is contributed by 29AjayKumar |
Javascript
// Function to move all the digit// at the beginning of the stringfunction moveAllDigitAtBeginning(str) { // Replace all the non-numeric // characters with "" and // replace all digits with "" let moveAllDigit = str.replace(/\D+/g, "") + str.replace(/\d+/g, ""); // Print the string console.log(moveAllDigit);}// Driver Codelet str = "neveropen1234";moveAllDigitAtBeginning(str);// contributed by akashish__ |
Output:
1234neveropen
Time Complexity: O(N)
Auxiliary Space: O(1)
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