How to Split a String between Numbers and Letters?

Problem Formulation: A list of letters and digits is provided. How to split up the string using the border between a letter and a number, and inversely, into substrings of either letters or numbers.

Split string without a predefined function

Divide the string str into three segments: a numeric segment; an alphabetic segment; and a segment with special characters.

Examples

1) Input : Java234T678point78!!!!
Output :JavaTpoint
        23467878
        !!!!
Here str = "Java567T123point!!!", Every character is scanned, and the string's res1, res2, and res3 are appended appropriately.

2) Input : **Java345T78point9##
Output: JavaTpoint
        345789
        **##

Steps

Determine the string's length.
Individually scan each character (ch) in a string
- Add it to the res1 string if (ch is a digit).
- Alternately, if (ch is an alphabet), add a string to res2.
- Else add it in string res3.
Print every string. We shall have three strings: one with a numeric component, one without a numeric component, and one with special characters..

Program

// java program to split an alphanumeric
// string using Stringbuffer
class check
{
static void splitString(String str)
    {
StringBuffer alpha = new StringBuffer(), 
        num = new StringBuffer(), special = new StringBuffer();
        for (int i=0; i<str.length(); i++)
{
            if (Character.isDigit(str.charAt(i)))
                num.append(str.charAt(i));
else if(Character.isAlphabetic(str.charAt(i)))
                alpha.append(str.charAt(i));
else
                special.append(str.charAt(i));
        }
System.out.println(alpha);
System.out.println(num);
System.out.println(special);
 }
 // Driver method
public static void main(String args[])
    {
String str = "Java234T567point890@#!!";
splitString(str);
}
}

Output:

How to Split a String between Numbers and Letters

Time Complexity: The preceding approach has an O(n) time complexity, where n is the length of the string.

Auxiliary Space: The space complexity of give code is O(n), where n is the string's length.

We can also split string on a regular expression like (?<=\D)(?=\d). Like this:

Program

public class JavaTpoint{
     public static void main(String []args){
     String str = "Javatpoint12345";
String[] part = str.split("(?<=\\D)(?=\\d)");
System.out.println(part[0]);
System.out.println(part[1]);
     }
}

Output:

So there are many ways to split string between number and characters. That are following:

Method: 1

public class JavaTpoint{
     public static void main(String []args){
    String st = "JavaTpoint123456789";
String st1=st.replaceAll("[^A-Za-z]", "");
String st2=st.replaceAll("[^0-9]", "");
System.out.println("String b = "+st1);
System.out.println("Int c = "+st2);
     }
}

Output:

Method: 2

public class JavaTpoint{
     public static void main(String []args){
 String input_string = "JavaTpoint98765";
String string_output=input_string.replaceAll("[^A-Za-z]", "");
int number_output=Integer.parseInt(input_string.replaceAll("[^0-9]", ""));
System.out.println("string_output = "+string_output);
System.out.println("number_output = "+number_output);
     }
}

Output:

Method: 3

public class MyClass {
public static void main(String args[]) {
  String a = "java123point456";
    int i;
    String str1="";
    String str2="";
    for(i = 0; i < a.length(); i++){
             char c = a.charAt(i);
                if( '0' <= c && c <= '9' )
                         str1=str1+c;
                if( 'a' <= c && c <= 'z' )
                         str2=str2+c;
       }
   System.out.println(str1);
   System.out.println(str2);
   }}

Output: