Scala Programming: Remove the character in a given position of a given string

Last update on February 05 2025 12:54:24 (UTC/GMT +8 hours)

Write a Scala program to remove the character in a given position of a given string. The given position will be in the range 0...string length -1 inclusive.

Pre-Knowledge (Before You Start!)

Before attempting this exercise, you should be familiar with the following concepts:

Scala Objects: Understanding how to define objects using the object keyword.
Functions in Scala: How to create functions with parameters and return values.
String Operations: Using methods like take() and drop() to manipulate substrings.
Indexing in Strings: Understanding that string indexing starts at 0 in Scala.
String Concatenation: Combining substrings using the + operator.
Main Method: Understanding the structure of the main() function in Scala.
Printing to Console: Using println() to display results.

Hints (Try Before Looking at the Solution!)

Try to solve the problem using these hints:

Hint 1: Define an object in Scala to contain the function.
Hint 2: Create a function that accepts a string and an integer (index position).
Hint 3: Use the take() method to extract the part of the string before the given index.
Hint 4: Use the drop() method to remove the character at the given index and keep the rest of the string.
Hint 5: Concatenate the two parts to form the modified string.
Hint 6: Call the function in the main() method with different test cases and print the results.
Hint 7: Consider edge cases like removing the first or last character.

Sample Solution:

Scala Code:

// Define an object named scala_basic
object scala_basic {
  // Define a function named test with parameters str of type String and n of type Int, returning a String
  def test(str: String, n: Int): String = 
    {
      // Take the substring of str from the beginning up to index n (exclusive), and concatenate it with
      // the substring of str starting from index n+1 to the end
      str.take(n) + str.drop(n + 1)
    }    

   // Define the main method, which is the entry point of the program
   def main(args: Array[String]): Unit = {
      // Print the result of calling test with the arguments "Scala" and 1
      println("Result: " + test("Scala", 1))

      // Print the result of calling test with the arguments "Scala" and 0
      println("Result: " + test("Scala", 0))

      // Print the result of calling test with the arguments "Scala" and 4
      println("Result: " + test("Scala", 4))
    }
}

Sample Output:

Result: Sala
Result: cala
Result: Scal

Explanation:

Here is the break down of the said Scala code:

object scala_basic {: This declares an object named scala_basic.
def test(str: String, n: Int): String =: This line defines a function named test that takes two parameters - a string str and an integer n. The function returns a string. It manipulates the input string by taking a substring up to index n (exclusive) and concatenating it with the substring starting from index n+1 to the end.
str.take(n) + str.drop(n + 1): This is the implementation of the test function. It uses the take method to get the substring from the beginning of str up to index n (exclusive), and then uses the drop method to get the substring starting from index n+1 to the end. These substrings are then concatenated.
def main(args: Array[String]): Unit = {: This line defines the main method, which is the entry point of the program. It takes an array of strings (args) as its parameter and returns Unit (similar to void in other languages).
println("Result: " + test("Scala", 1)): This line calls the "test()" function with the arguments "Scala" and 1, concatenates the result with the string "Result: ", and prints the entire string to the console.
println("Result: " + test("Scala", 0)): Similar to the previous line, this calls the "test ()" function with the arguments "Scala" and 0.
println("Result: " + test("Scala", 4)): Another call to the test function with the arguments "Scala" and 4.

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