How to remove leading and trailing whitespaces from a string in Kotlin

How to remove leading and trailing whitespaces from a string in Kotlin.

Here's a detailed step-by-step tutorial on how to remove leading and trailing whitespaces from a string in Kotlin.

Method 1: Using the trim() function

The easiest way to remove leading and trailing whitespaces from a string in Kotlin is by using the trim() function. This function removes all leading and trailing whitespace characters (including space, tab, and newline) from the given string.

Here's how you can use the trim() function:

val str = "   Hello, World!   "
val trimmedStr = str.trim()
println(trimmedStr) // Output: "Hello, World!"

In the above example, the trim() function is called on the str string, which removes the leading and trailing whitespaces. The resulting string, trimmedStr, is then printed to the console.

Method 2: Using the replace() function

If you need more control over which characters to remove, you can use the replace() function to replace specific characters with an empty string. This method allows you to specify the characters you want to remove using a regular expression.

Here's an example of using the replace() function to remove leading and trailing whitespaces:

val str = "   Hello, World!   "
val trimmedStr = str.replace("^\\s+|\\s+$".toRegex(), "")
println(trimmedStr) // Output: "Hello, World!"

In the above example, the regular expression "^\\s+|\\s+$" is used to match any leading (^\\s+) or trailing (\\s+$) whitespace characters. The replace() function replaces these characters with an empty string, effectively removing them.

Method 3: Using the Regex class

Another way to remove leading and trailing whitespaces is by using the Regex class. You can create a Regex object with the pattern "^\\s+|\\s+$" and then use the replace() function to remove the whitespaces.

Here's an example:

val str = "   Hello, World!   "
val regex = Regex("^\\s+|\\s+$")
val trimmedStr = regex.replace(str, "")
println(trimmedStr) // Output: "Hello, World!"

In this example, a Regex object is created with the pattern "^\\s+|\\s+$", which matches any leading or trailing whitespace characters. The replace() function is then used to replace these characters with an empty string.

Conclusion

In this tutorial, you learned three different methods to remove leading and trailing whitespaces from a string in Kotlin. The trim() function is the simplest method, while the replace() function and Regex class provide more flexibility. Choose the method that suits your needs the best and use it to remove whitespaces from your strings.