Keyword arguments in Ruby - Step-by-Step Execution

Concept Flow - Keyword arguments

Define method with keyword args

↓

Call method with keywords

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Match call keywords to params

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Execute method body using keywords

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Return result or output

The method is defined with named keyword arguments. When called, the keywords match parameters, then the method runs using those values.

Execution Sample

Ruby

def greet(name:, age:)
  "Hello, #{name}! You are #{age} years old."
end

puts greet(name: "Alice", age: 30)

Defines a method with keyword arguments and calls it with named values to print a greeting.

Execution Table

Step	Action	Keyword Argument	Value	Result/Output
1	Define method greet with keywords	name, age	none yet	Method ready
2	Call greet with keywords	name	"Alice"	Waiting for method body
3	Call greet with keywords	age	30	Waiting for method body
4	Match keywords to parameters	name	"Alice"	name = "Alice"
4	Match keywords to parameters	age	30	age = 30
5	Execute method body	name, age	"Alice", 30	"Hello, Alice! You are 30 years old."
6	puts outputs string	none	none	Hello, Alice! You are 30 years old.

💡 Method finishes after returning the greeting string and puts prints it.

Variable Tracker

Variable	Start	After Call	After Match	Final
name	undefined	passed "Alice"	"Alice"	"Alice"
age	undefined	passed 30	30	30

Key Moments - 3 Insights

Why do we write name: and age: in the method definition?

Because these define keyword arguments that must be passed by name when calling the method, as shown in execution_table rows 1 and 2.

What happens if we call greet without one keyword argument?

Ruby will raise an error because the method expects all keyword arguments to be provided, as implied by the matching step in execution_table row 4.

Can we change the order of keyword arguments when calling the method?

Yes, because keywords match by name, not position, so order does not matter (see execution_table rows 2 and 3).

Visual Quiz - 3 Questions

Look at the execution_table, what is the value of 'age' after matching keywords to parameters?

A undefined

B "Alice"

C 30

D nil

💡 Hint

Check execution_table row 4 where 'age' is matched to 30.

At which step does the method actually produce the greeting string?

A Step 2

B Step 5

C Step 4

D Step 6

💡 Hint

Look for the step where method body executes and returns the string (execution_table row 5).

If we call greet(age: 30, name: "Alice") instead, what changes in the execution_table?

A The matching order of keywords changes but final values stay the same

B The method will error because order changed

C The output string changes

D The method ignores the age argument

💡 Hint

Keyword arguments match by name, so order does not affect final variable values (see key_moments answer 3).

Concept Snapshot

def method_name(keyword1:, keyword2:)
  # use keyword1 and keyword2 inside
end

Call with method_name(keyword1: value1, keyword2: value2)

- Keywords must be named when calling
- Order does not matter
- Missing keywords cause errors

Full Transcript

This example shows how Ruby methods can use keyword arguments. The method greet is defined with two keywords: name and age. When calling greet, we pass values by naming them, like name: "Alice" and age: 30. Ruby matches these names to the parameters inside the method. Then the method uses these values to build a greeting string. Finally, puts prints the greeting. Keyword arguments help make code clearer by naming what each value means. They also allow arguments in any order but require all keywords to be given.