Print an Array Without Brackets and Commas

1. Introduction

When printing an Array, the default print format will print the values in brackets, with commas separating each element.

In this tutorial, we’ll learn how to print an Array without brackets and commas. We’ll explore several ways to achieve this, including core Java utility methods, Apache Commons Lang, and the Guava library.

2. Using StringBuilder

First, let’s look at using StringBuilder, which allows concatenating strings with the append() method. Specifically, we can traverse an Array and append its content using our StringBuilder. As a result, This will print an Array without brackets and commas and even allow us to add a custom separator.

For simplicity across the tutorial, we’ll use the same sample input in all our examples:

String[] content = new String[] { "www.", "Baeldung.", "com" };

Now, let’s loop through content and append() each element to our StringBuilder:

@Test
public void givenArray_whenUsingStringBuilder_thenPrintedArrayWithoutCommaBrackets() {
    StringBuilder builder = new StringBuilder();
    for (String element: content) {
        builder.append(element);
    }

    assertEquals("www.Baeldung.com", builder.toString());
}

Once we’ve added every element to the StringBuilder, we can print it without the brackets or separating commas.

3. Using String Manipulation

Arrays.toString() returns a string with the content of the input array. However, the new string created is a comma-delimited list of the array’s elements, with each element surrounded by square brackets:

"[www., Baeldung., com]"

We don’t want these brackets and commas in our final string. The String class provides different methods for replacing content from the specified text. Next, we’ll see how to use the replace() and replaceAll() methods to manipulate the string to remove the commas and brackets.

Please note that replace() and replaceAll() methods are useful only if our array content doesn’t contain commas or brackets. Otherwise, they will also be removed from the final output.

3.1. The replace() Method

To remove undesired characters, we can use the replace() method to specify the character we want to remove and its replacement character. This will search all occurrences of that character and replace it with the specified character.

First, we’ll print the array as a string with the brackets and commas. Then, we’ll call the replace() method for each unwanted character to remove them from our string:

@Test
public void givenArray_whenUsingStringReplace_thenPrintedArrayWithoutCommaBrackets() {
    String result = Arrays.toString(content)
        .replace("[", "")
        .replace("]", "")
        .replace(", ", "");

    assertEquals("www.Baeldung.com", result);
}

By replacing the unwanted characters with an empty string, we effectively remove them.

3.2. The replaceAll() Method

The replaceAll() method uses a regex pattern to replace the content.

Again, we’ll print the array to a string, and then provide the regex for the brackets and commas to remove the unwanted characters from the string:

public void givenArray_whenUsingStringReplaceAll_thenPrintedArrayWithoutCommaBrackets() {
    String result = Arrays.toString(content)
        .replaceAll("\\[|\\]|, ", "");

    assertEquals("www.Baeldung.com", result);
}

With this approach, we can specify all the character groups we want to remove in one complex regex expression.

4. Using String.join()

Java 8 and above provides a String.join() method that joins an input Array with the given delimiter:

@Test
public void givenArray_whenUsingStringJoin_thenPrintedArrayWithoutCommaBrackets() {
    String result = String.join("", content);

    assertEquals("www.Baeldung.com", result);
}

We’ll join the array with an empty string so that it will print without brackets or commas.

5. Java Streams API

Java 8 also introduced the Streams API. A Stream represents a sequence of objects that supports different operations that can be pipelined to produce the desired result. We’ll use the Streams API to join the Array content with the desired delimiter.

Let’s use Collectors.joining() to join the Array elements. We’ll also specify an empty string delimiter:

@Test
public void givenArray_whenUsingStream_thenPrintedArrayWithoutCommaBrackets() {
    String result = Stream.of(content).collect(Collectors.joining(""));

    assertEquals("www.Baeldung.com", result);
}

We created a stream of our content array with Stream.of() and then joined all elements with an empty string to generate a final string without commas and brackets.

6. Apache Commons Lang StringUtils.join()

The Apache Commons Lang library provides a StringUtils class with several types of join() methods. Furthermore, the most commonly used join() method is with the input Array and its delimiter:

@Test
public void givenArray_whenUsingStringUtilsJoin_thenPrintedArrayWithoutCommaBrackets() {
    String result = StringUtils.join(content, "");

    assertEquals("www.Baeldung.com", result);
}

Again, we join the elements of the array with an empty string.

7. Guava Joiner

The Guava library provides a Joiner utility class with an on() method where we can pass the delimiter. This will configure the delimiter and then return the instance of Joiner. Then, we call the join() method with our Array to join the content using that delimiter:

@Test
public void givenArray_whenUsingJoinerJoin_thenPrintedArrayWithoutCommaBrackets() {
    String result = Joiner.on("").join(content);

    assertEquals("www.Baeldung.com", result);
}

As a result, we join the elements of the array with an empty string.

8. Conclusion

We’ve explored different ways to print an Array without brackets and commas. Most methods also provide support for custom delimiters while joining the Array content. In particular, we explored the common Java utility class, Apache Commons Lang, and Guava library.