Java Program to Convert String to String Array

19 May, 2022
Given a String, the task is to convert the string into an Array of Strings in Java. It is illustrated in the below illustration which is as follows:
Illustration:
Input:  String : "Geeks for Geeks"
Output: String[]: [Geeks for Geeks]
Input: String    : "A computer science portal"
Output: String[] : [A computer science portal]
Methods:
They are as follows:
Using str.split() methodUsing loopsUsing Set.toArray() methodUsing String tokenizerUsing pattern.split() method
Using str.split() method
Using loops
Using Set.toArray() method
Using String tokenizer
Using pattern.split() method
Lets us now discuss every method in depth implementing the same to get a better understanding of the same. They are as follows: 
Method 1: Using str.split() method 
Approach:
Create an array with string type.
Split the given string using string_name.split().
Store splitted array into string array.
Print the above string array.
Example
Java
// Java Program to Convert String to String Array// Using str.split() method // Importing input output classesimport java.io.*; // Main classpublic class GFG {    // Main driver method    public static void main(String[] args)    {        // Input string to be convert to string array        String str = "Geeks for Geeks";         String strArray[] = str.split(" ");         System.out.println("String : " + str);        System.out.println("String array : [ ");         // Iterating over the string        for (int i = 0; i < strArray.length; i++) {            // Printing the elements of String array            System.out.print(strArray[i] + ", ");        }         System.out.print("]");    }}
String : Geeks for Geeks
String array : [ 
Geeks, for, Geeks, ]
Method 2: Using loops 
Approach: 
Get the set of strings.
Create an empty string array
Use advanced for loop, copy each element of set to the string array
Print the string array.
Example:
Java
// Java Program to Convert String to String Array// Using HashSet and Set classes // Importing required classes from respective packagesimport java.io.*;import java.util.Arrays;import java.util.HashSet;import java.util.Set; // Main classclass GFG {    // Method 1    //  To convert Set<String> to String[]    public static String[] method(Set<String> string)    {        // Create String[] of size of setOfString        String[] string_array = new String[string.size()];         // Copy elements from set to string array        // using advanced for loop         int index = 0;         for (String str : string) {            string_array[index++] = str;        }         // Return the formed String[]        return string_array;    }     // Method 2    // Main driver method    public static void main(String[] args)    {        // Custom input string        String str = "Geeks for Geeks";         // Getting the Set of String        Set<String> string_set            = new HashSet<>(Arrays.asList(str));         // Printing  the setOfString        System.out.println("String: " + str);         // Converting Set to String array        String[] String_array = method(string_set);         // Lastly printing the arrayOfString        // using Arrays.toString() method        System.out.println("Array of String: "                           + Arrays.toString(String_array));    }}
String: Geeks for Geeks
Array of String: [Geeks for Geeks]
Method 3: Using Set.toArray() method
Approach:
Convert the given string into set of string.
Now create an empty string array.
Convert the string set to Array of string using set.toArray() by passing an empty array of type string.
Print the array of string.
Example:
Java
// Java Program to Convert String to String Array// Using Set.toArray() method // Importing required classes from respective packagesimport java.io.*;import java.util.Arrays;import java.util.HashSet;import java.util.Set; // Main classpublic class GFG {     // Method 1    // To convert Set<String> to string array    public static String[] convert(Set<String> setOfString)    {         // Create String[] from setOfString        String[] arrayOfString            = setOfString.toArray(new String[0]);         // return the formed String[]        return arrayOfString;    }     // Method 2    // Main driver method    public static void main(String[] args)    {         // Custom input string as input        String str = "Geeks for Geeks";         // Getting the Set of String        Set<String> string            = new HashSet<>(Arrays.asList(str));         // Printing the setOfString        System.out.println("String: " + str);         // Converting Set to String array        String[] string_array = convert(string);         // Print the arrayOfString        // using Arrays.toString() method        System.out.println("String array : "                           + Arrays.toString(string_array));    }}
String: Geeks for Geeks
String array : [Geeks for Geeks]
Method 4: Using String tokenizer
String tokenizer helps to split a string object into smaller and smaller parts. These smaller parts are known as tokens.
Tokenize the given stringCreate an array of type string with the size of token counts.Store these tokens into a string array.Print the string array.
Tokenize the given string
Create an array of type string with the size of token counts.
Store these tokens into a string array.
Print the string array.
Example:
Java
// Java Program to Convert String to String Array// Using Set.toArray() method // Importing required classes from respective packagesimport java.io.*;import java.util.StringTokenizer; // Main classpublic class GFG {     // Main driver method    public static void main(String[] args)    {        // Declaring and initializing integer variable        // to zero        int i = 0;         // Custom input string as input        String str = "Geeks for Geeks";         // Tokenize a given string using the default        // delimiter        StringTokenizer str_tokenizer            = new StringTokenizer(str);         String[] string_array            = new String[str_tokenizer.countTokens()];        // Add tokens to our array         while (str_tokenizer.hasMoreTokens()) {            string_array[i] = str_tokenizer.nextToken();            i++;        }         // Print and display the string        System.out.print("String :" + str);         // Display message        System.out.print("\nString array : [ ");         // Printing the string array        // using for each loop        for (String string : string_array) {            System.out.print(string + " ");        }         System.out.print("]");    }}
String :Geeks for Geeks
String array : [ Geeks for Geeks ]
Method 5: Using pattern.split() method
The purpose of this pattern.split() method is to break the given string into an array according to a given pattern. We can split our string by giving some specific pattern. 
Approach:
Define pattern (REGEX)Then create a pattern using the compilation methodThen split the string using pattern.split() with a specific pattern and store it in the array.Print the string array
Define pattern (REGEX)
Then create a pattern using the compilation method
Then split the string using pattern.split() with a specific pattern and store it in the array.
Print the string array
Example:
Java
// Java Program to Convert String to String Array// Using Set.toArray() method // Importing required classes from respective packagesimport java.io.*;import java.util.regex.Pattern; // Main classpublic class GFG {    // Main driver method    public static void main(String[] args)    {        // Custom string as input        String str = "Geeks for Geeks";         // Step 1: Define REGEX        String my_pattern = "\\s";         // Step 2: Create a pattern using compile method        Pattern pattern = Pattern.compile(my_pattern);         // Step 3: Create an array of strings using the        // pattern we already defined        String[] string_array = pattern.split(str);         // Print and display string and        // its corresponding string array        System.out.print("String : " + str);        System.out.print("\nString array : [ ");         // Iterating over the string        for (int i = 0; i < string_array.length; i++) {            // Printing the string array            System.out.print(string_array[i] + " ");        }         System.out.print("]");    }}
String : Geeks for Geeks
String array : [ Geeks for Geeks ]
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