Java Program to Convert String to String Array
Last Updated :
19 May, 2022
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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() 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 Program to Convert String to String Array
// Using str.split() method
// Importing input output classes
import java.io.*;
// Main class
public 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("]");
}
}
Output
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 Program to Convert String to String Array
// Using HashSet and Set classes
// Importing required classes from respective packages
import java.io.*;
import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;
// Main class
class 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));
}
}
Output
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 Program to Convert String to String Array
// Using Set.toArray() method
// Importing required classes from respective packages
import java.io.*;
import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;
// Main class
public 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));
}
}
Output
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 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 Program to Convert String to String Array
// Using Set.toArray() method
// Importing required classes from respective packages
import java.io.*;
import java.util.StringTokenizer;
// Main class
public 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("]");
}
}
Output
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 method
- Then split the string using pattern.split() with a specific pattern and store it in the array.
- Print the string array
Example:
// Java Program to Convert String to String Array
// Using Set.toArray() method
// Importing required classes from respective packages
import java.io.*;
import java.util.regex.Pattern;
// Main class
public 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("]");
}
}
Output
String : Geeks for Geeks String array : [ Geeks for Geeks ]
