How do I remove white-space from the beginning of a string?

Question

How do I remove white-space from the beginning of a string in Java without removing from the end?

If the value is:

String temp = "    hi    "

Then how can I delete only the leading white-space so it looks like this:

String temp = "hi    "

The current implementation I have is to loop through, checking the first character and creating a substring until the first non-whitespace value is reached.

Thanks!

Solution 1

You could use:

temp = temp.replaceFirst("^\\s*", "")

Solution 2

You could use Commons-lang StringUtils stripStart method.

If you pass null it will automatically trim the spaces.

StringUtils.stripStart(temp, null);

Solution 3

As of JDK11 you can use stripLeading:

String result = temp.stripLeading();

Solution 4

Probably close to the implementation of the suggested Commons-lang StringUtils.stripStart() method:

public static String trimFront(String input) {
    if (input == null) return input;
    for (int i = 0; i < input.length(); i++) {
        if (!Character.isWhitespace(input.charAt(i)))
            return input.substring(i);
    }
    return "";
}

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Comments

[Brian]

This won't work with strings that already don't have whitespace. It should be temp.replaceFirst("^\\s*", ""); so that ^ matches the beginning of the string.

[Tim Bender]

The OP would also need to make sure the String starts with whitespace characters.

[Reimeus]

The ^ is only needed when using String.replaceAll. While it will work fine here, it is not needed for String.replaceFirst