将所有数字移动到给定字符串的开头
给定一个字符串 S ，任务是将字符串中的所有数字移动到字符串的开头。
示例:
输入:S = " geeks 4 forgek s123 " 输出:4123 geeks forgeks 解释: 给定字符串包含数字 4、1、2 和 3。将所有数字移到字符串的开头会将字符串修改为“4123GeeksforGeeks”。
输入:S= "geekforgesks 1234 A com 56 计算机科学门户 7 al " T5】输出:1234567 geekforgesks A 计算机科学门户
方法:思路是遍历字符串并维护两个字符串，一个字符串包含数字，另一个字符串包含非数字字符。最后，按照要求的顺序将两个字符串都附加到结果中。
下面是上述方法的实现:
Java 语言(一种计算机语言，尤用于创建网站)
// Java program for the above approach
class 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
= "GeeksforGeeks123";
moveAllDigitAtBeginning(str);
}
}
java 描述语言
<script>
// JavaScript program for the above approach
// Function to move all the digit
// to the beginning of the string
function 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 str
var str = "GeeksforGeeks123";
moveAllDigitAtBeginning(str);
// This code is contributed by rdtank
</script>
Output:
123GeeksforGeeks
时间复杂度:O(N) T5辅助空间:** O(1)
正则表达式 基于方法:给定的问题也可以使用正则表达式解决，用空字符串 (" ") 代替所有非数字字符，用空字符串 (" ") 代替所有数字字符。最后，连接字符串并打印结果。
下面是上述方法的实现:
Java 语言(一种计算机语言，尤用于创建网站)
// Java program for the above approach
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 = 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
= "GeeksforGeeks1234";
moveAllDigitAtBeginning(str);
}
}
C
// C# program for the above approach
using 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
= "GeeksforGeeks1234";
moveAllDigitAtBeginning(str);
}
}
// This code is contributed by 29AjayKumar
Output:
1234GeeksforGeeks
时间复杂度:O(N) T5辅助空间:** O(1)
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