Converting String to "Character" array in Java

Question

I want to convert a String to an array of objects of Character class but I am unable to perform the conversion. I know that I can convert a String to an array of primitive datatype type "char" with the toCharArray() method but it doesn't help in converting a String to an array of objects of Character type.

How would I go about doing so?

Answer 1

---

String[] arr = { "abc", "cba", "dac", "cda" };
    Map<Character, Integer> map = new HashMap<>();
    String string = new String();
    for (String a : arr) {
        string = string.concat(a);

    }
    System.out.println(string);

    for (int i = 0; i < string.length(); i++) {
        if (map.containsKey(string.charAt(i))) {
            map.put(string.charAt(i), map.get(string.charAt(i)) + 1);

        } else {
            map.put(string.charAt(i), 1);

        }
    }
    System.out.println(map);

//out put {a=4, b=2, c=4, d=2}

Answer 2

Why not write a little method yourself

public Character[] toCharacterArray( String s ) {

   if ( s == null ) {
     return null;
   }

   int len = s.length();
   Character[] array = new Character[len];
   for (int i = 0; i < len ; i++) {
      /* 
      Character(char) is deprecated since Java SE 9 & JDK 9
      Link: https://docs.oracle.com/javase/9/docs/api/java/lang/Character.html
      array[i] = new Character(s.charAt(i));
      */
      array[i] = s.charAt(i);
   }

   return array;
}

Answer 3

Converting String to Character Array and then Converting Character array back to String

   //Givent String
   String given = "asdcbsdcagfsdbgdfanfghbsfdab";

   //Converting String to Character Array(It's an inbuild method of a String)
   char[] characterArray = given.toCharArray();
   //returns = [a, s, d, c, b, s, d, c, a, g, f, s, d, b, g, d, f, a, n, f, g, h, b, s, f, d, a, b]

//ONE WAY : Converting back Character array to String

  int length = Arrays.toString(characterArray).replaceAll("[, ]","").length();

  //First Way to get the string back
  Arrays.toString(characterArray).replaceAll("[, ]","").substring(1,length-1)
  //returns asdcbsdcagfsdbgdfanfghbsfdab
  or 
  // Second way to get the string back
  Arrays.toString(characterArray).replaceAll("[, ]","").replace("[","").replace("]",""))
 //returns asdcbsdcagfsdbgdfanfghbsfdab

//Second WAY : Converting back Character array to String

String.valueOf(characterArray);

//Third WAY : Converting back Character array to String

Arrays.stream(characterArray)
           .mapToObj(i -> (char)i)
           .collect(Collectors.joining());

Converting string to Character Array

Character[] charObjectArray =
                           givenString.chars().
                               mapToObj(c -> (char)c).
                               toArray(Character[]::new);

Converting char array to Character Array

 String givenString = "MyNameIsArpan";
char[] givenchararray = givenString.toCharArray();


     String.valueOf(givenchararray).chars().mapToObj(c -> 
                         (char)c).toArray(Character[]::new);

benefits of Converting char Array to Character Array you can use the Arrays.stream funtion to get the sub array

String subStringFromCharacterArray = 

              Arrays.stream(charObjectArray,2,6).
                          map(String::valueOf).
                          collect(Collectors.joining());

Answer 4

I used the StringReader class in java.io. One of it's functions read(char[] cbuf) reads a string's contents into an array.

String str = "hello";
char[] array = new char[str.length()];
StringReader read = new StringReader(str);

try {
    read.read(array); //Reads string into the array. Throws IOException
} catch (IOException e) {
    e.printStackTrace();
}

for (int i = 0; i < str.length(); i++) {
        System.out.println("array["+i+"] = "+array[i]);
}

Running this gives you the output:

array[0] = h
array[1] = e
array[2] = l
array[3] = l
array[4] = o

Answer 5

One liner with java-8:

String str = "testString";

//[t, e, s, t, S, t, r, i, n, g]
Character[] charObjectArray = 
    str.chars().mapToObj(c -> (char)c).toArray(Character[]::new); 

What it does is:

• get an IntStream of the characters (you may want to also look at codePoints())
• map each 'character' value to Character (you need to cast to actually say that its really a char, and then Java will box it automatically to Character)
• get the resulting array by calling toArray()

Answer 6

If you don't want to rely on third party API's, here is a working code for JDK7 or below. I am not instantiating temporary Character Objects as done by other solutions above. foreach loops are more readable, see yourself :)

public static Character[] convertStringToCharacterArray(String str) {
    if (str == null || str.isEmpty()) {
        return null;
    }
    char[] c = str.toCharArray();
    final int len = c.length;
    int counter = 0;
    final Character[] result = new Character[len];
    while (len > counter) {
        for (char ch : c) {
            result[counter++] = ch;
        }
    }
    return result;
}

Answer 7

This method take String as a argument and return the Character Array

/**
 * @param sourceString
 *            :String as argument
 * @return CharcterArray
 */
public static Character[] toCharacterArray(String sourceString) {
    char[] charArrays = new char[sourceString.length()];
    charArrays = sourceString.toCharArray();
    Character[] characterArray = new Character[charArrays.length];
    for (int i = 0; i < charArrays.length; i++) {
        characterArray[i] = charArrays[i];
    }
    return characterArray;
}

Answer 8

Use this:

String str = "testString";
char[] charArray = str.toCharArray();
Character[] charObjectArray = ArrayUtils.toObject(charArray);

Answer 9

chaining is always best :D

String str = "somethingPutHere";
Character[] c = ArrayUtils.toObject(str.toCharArray());

Answer 10

if you are working with JTextField then it can be helpfull..

public JTextField display;
String number=e.getActionCommand();

display.setText(display.getText()+number);

ch=number.toCharArray();
for( int i=0; i<ch.length; i++)
    System.out.println("in array a1= "+ch[i]);

Answer 11

I hope the code below will help you.

String s="Welcome to Java Programming";
char arr[]=s.toCharArray();
for(int i=0;i<arr.length;i++){
    System.out.println("Data at ["+i+"]="+arr[i]);
}

It's working and the output is:

Data at [0]=W
Data at [1]=e
Data at [2]=l
Data at [3]=c
Data at [4]=o
Data at [5]=m
Data at [6]=e
Data at [7]= 
Data at [8]=t
Data at [9]=o
Data at [10]= 
Data at [11]=J
Data at [12]=a
Data at [13]=v
Data at [14]=a
Data at [15]= 
Data at [16]=P
Data at [17]=r
Data at [18]=o
Data at [19]=g
Data at [20]=r
Data at [21]=a
Data at [22]=m
Data at [23]=m
Data at [24]=i
Data at [25]=n
Data at [26]=g

Answer 12

You have to write your own method in this case. Use a loop and get each character using charAt(i) and set it to your Character[] array using arrayname[i] = string.charAt[i].

Answer 13

String#toCharArray returns an array of char, what you have is an array of Character. In most cases it doesn't matter if you use char or Character as there is autoboxing. The problem in your case is that arrays are not autoboxed, I suggest you use an array of char (char[]).

Answer 14

another way to do it.

String str="I am a good boy";
    char[] chars=str.toCharArray();

    Character[] characters=new Character[chars.length];
    for (int i = 0; i < chars.length; i++) {
        characters[i]=chars[i];
        System.out.println(chars[i]);
    }