Kotlin Strings

In Kotlin, a String is used to store a sequence of characters. Strings are immutable, which means once created, they cannot be changed.

1. Creating Strings

val name = "Kotlin"
val message: String = "Welcome to Kotlin"

2. String Length

val text = "Hello"
println(text.length) // 5

3. Access Characters in a String

val word = "Kotlin"
println(word[0]) // K
println(word[3]) // l

4. String Concatenation

Using + Operator

val first = "Hello"
val second = "Kotlin"println(first + ” “ + second)

Using String Templates (Recommended)

val lang = "Kotlin"
println("Welcome to $lang")

5. String Templates with Expressions

val a = 10
val b = 20println(“Sum = ${a + b}“)

6. Multi-Line Strings (Triple Quotes)

val text = """
Kotlin is modern
Easy to learn
Powerful language
"""
println(text)

7. Common String Functions

val str = "Kotlin Programming"

println(str.uppercase())
println(str.lowercase())
println(str.length)
println(str.contains(“Kotlin”))
println(str.replace(“Kotlin”, “Java”))

8. Compare Strings

Structural Equality (==)

val a = "Kotlin"
val b = "Kotlin"println(a == b) // true

Referential Equality (===)

println(a === b) // true or false (memory reference)

9. Check Empty or Blank

val s1 = ""
val s2 = " "println(s1.isEmpty()) // true
println(s2.isBlank()) // true

10. Escape Characters

println("Hello\nKotlin") // New line
println("Hello\tKotlin") // Tab
println("She said \"Hi\"")

11. Nullable Strings

var name: String? = null
println(name?.length) // Safe call

Summary

  • Strings are immutable

  • Supports string templates

  • Rich built-in functions

  • Supports multi-line strings

Next Topics You Can Learn

  • Kotlin String Functions (Deep)

  • Kotlin Arrays

  • Kotlin Conditions

  • Kotlin Input

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