How to add spaces to left and right of chars in a string?

Question

I'm trying to print out a string with spaces on either side of each char in the string

so if I have

String s = "abcde"

it would create something like this

 a   b   c   d   e 

with a space before the first char and three between each char.

I just haven't been able to find a way to do this with my knowledge.

Answer 1

Update

Updated requirement:

I failed to realize that I need something that add one place in front of the first term and then 3 spaces between each term. _0___0___0___0___0_ for example.

For the updated requirement, you can use yet another cool thing, String#join.

public class Main {
    public static void main(String[] args) {
        String s = "abcde";

        String result = "_" + String.join("___", s.split("")) + "_";

        System.out.println(result);
    }
}

Output:

_a___b___c___d___e_

Original answer

There can be so many ways to do it. I find it easier to do it using Regex:

public class Main {
    public static void main(String[] args) {
        String s = "abcde";
        String result = s.replaceAll(".", " $0 ");
        System.out.println(result);
    }
}

Output:

 a  b  c  d  e 

The Regex, . matches a single character and $0 replaces this match with space + match + space.

Another cool way is by using Stream API.

import java.util.Arrays;
import java.util.stream.Collectors;

public class Main {
    public static void main(String[] args) {
        String s = "abcde";
        
        String result = Arrays.stream(s.split(""))
                                .map(str -> " " + str + " ")
                                .collect(Collectors.joining());
        
        System.out.println(result);
    }
}

Output:

 a  b  c  d  e 

Answer 2

A super simple example, that doesn't handle a multitude of potential input scenarios.

    public static void main(String[] args)
    {
        String s = "abcde";
        
        
        for (int i = 0; i < s.length(); ++i) {
            System.out.print("_" + s.charAt(i));
        }
        System.out.println("_");
    }

NOTE: used an underscore rather than a space in order to allow visual check of the output.

Sample output:

_a_b_c_d_e_

Rather than direct output, one could use a StringBuilder and .append to a builder instead, for example.

Using StringBuilder:

        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < s.length(); ++i) {
            sb.append('_').append(s.charAt(i));
        }
        sb.append('_');        
        
        System.out.println(sb.toString());

Based on a comment where the desired output is slightly different (two internal spaces, one leading and trailing space), this suggests an alternative approach:

   public static String addSpace(String inp) {
        StringBuilder sB = new StringBuilder();
        
        String string = inp.trim();
        
        String div = "___";  // spaces, or whatever
        
        
        sB.append('_');  // add leading space
        for(int index = 0; index < string.length(); ++index) {
            sB.append(string.charAt(index))
                .append(div);  // two spaces  
         }
        sB.setLength(sB.length() - (div.length() - 1) );
        
        return (sB.toString());
    }

NOTE: again using an underscore to allow for easier debugging.

Output when div is set to 3 underscores (or spaces):

_0___0___0___1___0___1___1___0_

Answer 3

You can define an empty string : result = “”;

Then go through the string you want to print with foreach loop With the function toCharArray()

(char character : str.toCharArray())

And inside this loop do ->

result += “ “ + character;

Answer 4

String result = s.chars().mapToObj(
                       Character::toString
                   ).collect(Collectors.joining(" "));

Similar to the loop versions, but uses a Stream.

Answer 5

Another one liner to achieve this, by splitting the String into String[] of characters and joining them by space:

public class Main {
    public static void main(String[] args) {
        String s = "abcde";
        System.out.println(" " + String.join("  ", s.split("")) + " ");
    }
}

Output: a b c d e

Edit: The above code won't work for strings with Unicode codepoints like "ab", so instead of splitting on empty string, the split should be performed on regex: "(?<=.)".

public class Main {
    public static void main(String[] args) {
        String s = "abcde";
        System.out.println(" " + String.join("  ", s.split("(?<=.)")) + " ");
    }
}

Thanks to @saka1029 for pointing this out.

Answer 6

You can use Collectors.joining(delimiter,prefix,suffix) method with three parameters:

String s1 = "abcde";

String s2 = Arrays.stream(s1.split(""))
        .collect(Collectors.joining("_+_", "-{", "}-"));

System.out.println(s2); // -{a_+_b_+_c_+_d_+_e}-

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^{See also: How to get all possible combinations from two arrays?}