Decision Making in Ruby with if else Statements

Decision Making in Ruby

In Ruby, decision-making is accomplished using conditional statements that allow developers to execute different blocks of code based on certain conditions. Conditional statements in Ruby evaluate expressions to either true or false, which is used to determine which block of code to execute.

Decision Making Statement in Ruby

The primary decision-making statement in Ruby is the if statement. It is used to execute a block of code if a certain condition is true. The basic syntax of the if statement is as follows:

Here, the expression is a Boolean value or an expression that evaluates to a Boolean value. If the expression is true, then the code inside the if block is executed. If the expression is false, then the code is skipped.

Understanding Truthy and Falsy Values in Ruby

In Ruby, every object has a boolean value, that is every object is evaluated as true or false. An object that is considered true in a Boolean context is called truthy, while a value that is considered false in a Boolean context is called falsy. The following values are considered falsy in Ruby:

• nil
• false

Everything else is considered truthy, including:

• 0 - numeric zero (Integer or otherwise)
• "" - Empty strings
• "\n" - Strings containing only whitespace
• [] - Empty arrays
• {} - Empty hashes

Types of Condition in Ruby

In Ruby, there are two types of conditions: simple conditions and compound conditions. Simple conditions use comparison operators to evaluate expressions, while compound conditions use logical operators to evaluate multiple expressions.

Basic Conditions Using Comparison Operators

Ruby provides a range of comparison operators that can be used to evaluate expressions. The following operators are commonly used in Ruby:

Using Multiple Conditions in Ruby

Ruby provides two logical operators, AND (&&) and OR (||), that can be used to combine multiple conditions. The AND operator is used to execute code only if both conditions are true, while the OR operator is used to execute code if either condition is true.

Example

In this example both the conditions b > a and b > c is true, so the expression (b > a && b > c) evaluates to true.

If Statement in Ruby

The if statement is used to execute a block of code if a certain condition is true.

Syntax

Example

Here, the code inside the if block is executed because the expression x == y evaluates to true.

If else Statement in Ruby

The if statement is used to execute a block of code if a certain condition is true. However, sometimes we want to execute a different block of code if the condition is false. In such cases, we can use the if else in Ruby.

Syntax

Example

Here, the code inside the else block is executed because the expression x > y evaluates to false.

If-elsif-else Ladder in Ruby

Sometimes, we need to check for multiple conditions and execute different blocks of code based on those conditions. In such cases, we can use the if-elsif-else ladder.

Syntax

Example

Here, the first expression evaluates to false. The second expression (x % 2 == 0) evaluates to true and so the block of code inside the first elsif statement is executed.

Case Statements in Ruby

Another way to express complex conditional logic is by using case statements. The case statements allow us to compare a single value against a series of possible values and execute different blocks of code based on the matching value

Syntax

Example

In this example, the condition that evaluates to true is when 'B', so the corresponding block of code gets executed.

Unless Statements in Ruby

In Ruby, we can also use the unless statement to express a negative condition. The unless statement is used to execute a block of code if a certain condition is false.

Syntax

Here, if the expression is false, the code inside the unless block is executed.

Example

In this example, the expression x >= y evaluates to false. So the code in the unless block gets executed.

Ternary Operator in Ruby

A ternary operator in Ruby is a shorthand way of writing a conditional expression. It consists of three parts: a condition, a true expression, and a false expression.

Syntax

If the condition is true, then the true_expression is evaluated, otherwise the false_expression is evaluated.

Example

When Should We Use a Ternary Expression?

Ternary operators are useful in situations where you need to make a quick decision based on a condition. They can make code more concise and easier to read in certain situations. However, it's important to use them judiciously and not to overuse them, as they can sometimes make code harder to read and understand.