Replace in Kotlin

To replace a substring within a string in Kotlin, you can use the replace function which takes two arguments: the substring to be replaced and the new substring to replace it with.

Here is an example of how to replace a substring within a string:

fun main() {
    val str = "The quick brown fox jumps over the lazy dog."
    val newStr = str.replace("lazy", "energetic")
    println(newStr)
}

Output:

The quick brown fox jumps over the energetic dog.

In this example, we first declared a str variable and initialized it with a string that contains the word "lazy". We then used the replace function to replace the word "lazy" with "energetic" and assigned the result to a new variable newStr. Finally, we printed the new string newStr to the console.

You can also use the replaceFirst or replaceLast functions to replace only the first or last occurrence of a substring, respectively. These functions take the same arguments as replace.

Here's an example of using replaceFirst:

fun main() {
    val str = "The quick brown fox jumps over the lazy dog."
    val newStr = str.replaceFirst("lazy", "energetic")
    println(newStr)
}

Output:

The quick brown fox jumps over the energetic dog.

In this example, only the first occurrence of the word "lazy" is replaced with "energetic".