Skip to main content

How to remove all special characters from a string in Kotlin

How to remove all special characters from a string in Kotlin.

Here is a step-by-step tutorial on how to remove all special characters from a string in Kotlin:

Step 1: Create a function to remove special characters.​

fun removeSpecialCharacters(str: String): String {
    // Regex pattern to match special characters
    val regexPattern = Regex("[^a-zA-Z0-9 ]")
    
    // Replace special characters with an empty string
    return str.replace(regexPattern, "")
}

Step 2: Call the removeSpecialCharacters function with a string parameter.

val inputString = "Hello!@# World!$%"
val result = removeSpecialCharacters(inputString)
println(result)

Output: Hello World

Step 3: Test the function with different strings containing special characters.

val inputString1 = "Hello#@123"
val inputString2 = "Testing!!"
val inputString3 = "Hello World"

val result1 = removeSpecialCharacters(inputString1)
val result2 = removeSpecialCharacters(inputString2)
val result3 = removeSpecialCharacters(inputString3)

println(result1) // Output: Hello123
println(result2) // Output: Testing
println(result3) // Output: Hello World

Step 4: Remove special characters using a regular expression.​

val inputString = "Hello!@# World!$%"

// Remove special characters using regex
val result = inputString.replace(Regex("[^a-zA-Z0-9 ]"), "")

println(result)

Output: Hello World

Step 5: Remove special characters using a combination of regex and filter.

val inputString = "Hello!@# World!$%"

// Remove special characters using regex and filter
val result = inputString.filter { it.isLetterOrDigit() || it.isWhitespace() }

println(result)

Output: Hello World

Step 6: Remove special characters using a character blacklist.​

val inputString = "Hello!@# World!$%"

// List of special characters to be removed
val specialCharacters = listOf('!', '@', '#', '$', '%')

// Remove special characters using a character blacklist
val result = inputString.filter { it !in specialCharacters }

println(result)

Output: Hello World

That's it! You now know how to remove all special characters from a string in Kotlin using different approaches. Feel free to choose the method that suits your needs the best.