How to Convert String to Array in Java

The Challenge

Convert a string into an array of characters or words!

Solutions

Method 1: String to Character Array

java

String text = "Hello";
char[] charArray = text.toCharArray();

for (char c : charArray) {
    System.out.print(c + " ");
}
// Output: H e l l o

Method 2: String to Word Array

java

String text = "Java is fun";
String[] words = text.split(" ");

for (String word : words) {
    System.out.println(word);
}
// Output:
// Java
// is
// fun

Method 3: Split by Custom Delimiter

java

String text = "apple,banana,cherry";
String[] fruits = text.split(",");

System.out.println(Arrays.toString(fruits));
// Output: [apple, banana, cherry]

Did You Know?

The split() method uses regex! Use split("\\.") to split by period (escape special characters).

Pro Tip

Split with limit to control array size:

java

String text = "a,b,c,d,e";
String[] parts = text.split(",", 3);
System.out.println(Arrays.toString(parts));
// Output: [a, b, c,d,e]

Real-World Use Cases

CSV parsing: Split comma-separated values
Text processing: Analyze individual characters
Data extraction: Parse structured text
Tokenization: Break text into tokens

›Short versionOpen if you only have a minute.

toCharArray() returns the char values. It does not split words.
split takes a regex. The dot matches any character.
"a.b.c".split(".") does not return ["a", "b", "c"]. Escape the dot as "\\.".
Repeated delimiters produce empty tokens. Decide whether those tokens are data.

String to array

Turn text into chars, or into tokens, depending on the next step.

Working approach

Use toCharArray when the next loop wants characters.
Use split with a regex you meant, and escape metacharacters.
Use a real CSV parser for CSV. split(",") breaks on quoted commas.

Walk the sample

Input "a,b,c"
The delimiter is a literal comma
The array is ["a", "b", "c"]

The trap

split(".") looks like a literal dot and behaves as "split on every character". Default split then drops the trailing empty tokens.

java

String[] letters = "a.b.c".split("\\.");   // ["a", "b", "c"]
char[] chars = "a.b.c".toCharArray();         // five chars, including the dots

// "a.b.c".split(".") does not produce the three letters

What does "a.b.c".split(".") give you?

The pattern . matches any character, so every character is a delimiter.

The tokens between those delimiters are empty, and split discards trailing empties, so you do not get ["a", "b", "c"]. The escaped pattern "\\." does.

Time O(n), space O(n).

Easy to get wrong

Calling split(".") to split on a dot.
Using toCharArray when the next step wanted words.