Exploring Comparison Operators in Scala | CodeSignal Learn

Exploring Comparison Operators in Scala | CodeSignal Learn

Introduction and Lesson Overview

Greetings! Today, we're learning about comparison operators in Scala. This fundamental concept is central to decision-making in coding. As part of our lesson, we will delve into a range of examples involving various data types to comprehend their usage. So, let's dive into the discovery!

Understanding Comparison Operators

Suppose you attend a daily contest in which we gauge who's taller or faster. If we replace these parameters with "greater," "lesser," "equal," or "not equal," we will have the comparison operators! Scala employs several principal ones: Equal to (==) Not equal to (!=) Greater than (>) Less than (<) Greater than or equal to (>=) Less than or equal to (<=) Let's examine these operators using simple examples: Scala @main def run: Unit = val num1 = 5 val num2 = 10 println(num1 == num2) // prints: false, as 5 is not equal to 10 println(num1 != num2) // prints: true, as 5 is not equal to 10 println(num1 > num2) // prints: false, as 5 is not greater than 10 println(num1 < num2) // prints: true, as 5 is less than 10 println(num1 >= num2) // prints: false, as 5 is not greater than or equal to 10 println(num1 <= num2) // prints: true, as 5 is less than or equal to 10 These comparisons of 5 and 10 using the operators yield boolean values (true or false).

Applying Comparison Operators on Numbers

Imagine two siblings: Harry, aged 12, and Ron, aged 14. We can compare their ages using comparison operators: Scala @main def run: Unit = val ageHarry = 12 val ageRon = 14 println(ageHarry == ageRon) // prints: false, as Harry and Ron are of different ages println(ageHarry != ageRon) // prints: true, as above println(ageHarry > ageRon) // prints: false, as Harry is younger than Ron println(ageHarry < ageRon) // prints: true, as Harry is younger than Ron println(ageHarry >= ageRon) // prints: false, as Harry is younger or not as old as Ron println(ageHarry <= ageRon) // prints: true, as Harry is younger or as old as Ron (in this case, younger)

Comparison Operators with Booleans

Now, let's compare Boolean variables. Please note that we use the operators == and!= in this case: Scala @main def run: Unit = val isMorning = true val isAfternoon = false println(isMorning == isAfternoon) // prints: false, as true is not the same as false println(isMorning != isAfternoon) // prints: true, as true is not equal to false

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Comparing Characters and Strings

In Scala, comparing characters (Char) works similarly to comparing numbers. The character that comes first alphabetically is "less than" the one that follows. Note, however, that Scala considers capital letters as "less than" lowercase letters because of their arrangement in the Unicode system. For strings (String), we use the == operator, which performs a case-sensitive comparison. Additionally, the operators >, <, >=, and <= are used to make comparisons in lexicographic order. Let's try comparing the characters 'a' and 'b', as well as the strings "alpha" and "beta": @main def run: Unit = val char1 = 'a' val char2 = 'b' println(char1 == char2) // prints: false, as 'a' is not the same as 'b' println(char1 != char2) // prints: true, as 'a' and 'b' are different println(char1 > char2) // prints: false, as 'a' comes before 'b' in the alphabet println(char1 < char2) // prints: true, as above println(char1 >= char2) // prints: false, as 'a' is not after or at the same position as 'b' println(char1 <= char2) // prints: true, as 'a' is before or at the same position as 'b' (in this case, before) val string1 = "alpha" val string2 = "beta" println(string1 == string2) // prints: false, because "alpha" and "beta" are different words println(string1 > string2) // prints: false, because "alpha" comes before "beta" in lexicographic order println(string1 < string2) // prints: true, because "alpha" comes before "beta" in lexicographic order Note for Java developers: In Scala, the == operator performs a value-based comparison for strings, similar to Java's String.equals method. This means you don't need to use equals explicitly for checking string equality, reducing the risk of mistakenly checking reference equality as often seen with the == operator in Java.

Scala

@main def run: Unit = 
  val char1 = 'a'
  val char2 = 'b'

  println(char1 == char2)     // prints: false, as 'a' is not the same as 'b'
  println(char1 != char2)     // prints: true, as 'a' and 'b' are different
  println(char1 > char2)      // prints: false, as 'a' comes before 'b' in the alphabet
  println(char1 < char2)      // prints: true, as above
  println(char1 >= char2)     // prints: false, as 'a' is not after or at the same position as 'b'
  println(char1 <= char2)     // prints: true, as 'a' is before or at the same position as 'b' (in this case, before)

  val string1 = "alpha"
  val string2 = "beta"

  println(string1 == string2)  // prints: false, because "alpha" and "beta" are different words
  println(string1 > string2)   // prints: false, because "alpha" comes before "beta" in lexicographic order
  println(string1 < string2)   // prints: true, because "alpha" comes before "beta" in lexicographic order