Removing all occurrences of a character from string without replace method

Question

I need to write a method called remove() that takes two arguments, a String and a char , and returns a new String that removes all occurrences of the char from the input String. I have to do this without using the replace() method. So far I have:

public class Remover
{
   public static void main (String[] args)
    {
        String sampleString = "this is some text";
        char sampleChar = 's';
        System.out.print(remove(sampleString, sampleChar));
    }
    public static String remove(String a, char b)
    {
      String newString = "";
        newString = a.substring(0, a.indexOf(b))+""+a.substring(a.indexOf(b)+1);

        return newString;
    }
}

The main method is just there for testing purposes and the sample string and char are just examples; I need this method to work for any string and char. But either way, I'm sure what I have is wrong and I'm completely lost on how to proceed. For this case, I'm trying to get my code to return

"thi i ome text"

Answer 1

1. Get char array from the string using string.toCharArray() method.
2. Traverse the char array. Append the char to a String if it is not equal to your target char
3. Use StringBuilder class for appending: building the string.

Answer 2

You can iterate through the String using charAt()

String s = "this is some text";

public static String remove(String a, char b) {

    String word = "";

    for (int i = 0; i < a.length(); i++){
        if (s.charAt(i) != b){
            word += a.charAt(i);
        }
    }

    return word;

}

An alternative to String concatenating is to use StringBuilder inside the loop

StringBuilder sb = new StringBuilder();

for (int i = 0; i < a.length(); i++){
    if (s.charAt(i) != b){
        sb.append(s.charAt(i));
    }
}

return sb.toString();

Another way to approach this is to convert the String to a char array and traverse the array

 StringBuilder sb = new StringBuilder;

 for (char c : s.toCharArray()){
     if (c != b) {
         sb.append(c);
     }   
 }

 return word;

Answer 3

I'll not suggest an alternative solution , I'll tell you how to fix the problem in your current code.

Your program works only for the first occurrence of s . You should do the following:

1. Split the string according to " " .
2. Pass each word in the array to remove method.
3. Print the result on the same line with " " .

Should have something like that:

String sampleString = "this is some text";
String[] arr = sampleString.split(" ");
char sampleChar = 's';
for(String str : arr) {
    System.out.print(remove(str, sampleChar) + " ");
}

Note that in remove method, you should check if the String contains s , if not, return it as it is:

public static String remove(String a, char b) {
   if(!a.contains(b)) {
      return a;
   }
   String newString = "";
   newString = a.substring(0, a.indexOf(b))+""+a.substring(a.indexOf(b)+1);
   return newString;
}

This should work.

Answer 4

You can use recursion like below. But still use StringBuilder,that s the better way. This is just to make your code work

public static String remove(String a, char b)
{
   String newString = "";
   newString = a.substring(0, a.indexOf(b))+""+a.substring(a.indexOf(b)+1);
   if(newString.indexOf(b)!=-1) {
     newString= remove(newString,b);
   }
   return newString;
}

Answer 5

You can convert the source string to char array using a.toCharArray()) ,

then write a for-loop to compare the char element in char array one-by-one with expected removed char.

If it is not equal, then append it to StringBuilder object.

have a try with this;

 public static String remove(String a, char b) {
    /*String newString = "";
    newString = a.substring(0, a.indexOf(b)) + ""
            + a.substring(a.indexOf(b) + 1);

    return newString;*/

    StringBuilder sb = new StringBuilder();

    for(char c: a.toCharArray())
    {
        if(c!= b)
        {
            sb.append(c);
        }
    }
    return sb.toString();
}

Answer 6

public class charReplace{
    public static void main(String args[]){
    String sampleString = "This is some text";
    char sampleChar = 's';
    System.out.println(char_remove(sampleString, sampleChar));
}

public static String char_remove(String a, char b){
    String newString = " ";
    int len = a.length();
    for(int i =0; i<len ;i++)
     {
       char c = a.charAt(i);
       if(c == b)
          newString = newString + " ";
       else
          newString = newString + c ;  
     }
    return newString;
  }
}

Answer 7

 public static String remove(String a, char b)
    {
       StringBuilder sbul =new StringBuilder();
       int i;
        for(i=0;i<a.length();i++){
              char c = a.charAt(i);
               if(c==b)
                  continue;
                sbul.append(c);
             }
        return sbul.toString();
}