Send for calling methods dynamically in Ruby - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the send method do in Ruby?

The send method calls another method by name dynamically, allowing you to invoke methods using a symbol or string representing the method's name.

beginner

How do you use send to call a method named greet on an object obj?

You write obj.send(:greet). This calls the greet method on obj dynamically.

intermediate

Can send pass arguments to the method it calls? How?

Yes. You pass arguments after the method name symbol. For example, obj.send(:add, 5, 3) calls add(5, 3) on obj.

intermediate

What is the difference between send and public_send?

send can call any method, including private ones. public_send only calls public methods and will raise an error if the method is private.

beginner

Why is send useful in Ruby programming?

It allows flexible and dynamic method calls, useful when method names are not known until runtime, like in metaprogramming or when handling user input.

What argument type does send expect for the method name?

A Symbol or String

B Integer

C Boolean

D Array

send expects the method name as a symbol or string to call it dynamically.

Which method allows calling private methods: send or public_send?

A Neither

B public_send

C send

D Both

send can call private methods, but public_send cannot.

What happens if you use public_send to call a private method?

A It calls the method successfully

B It calls the method but warns

C It returns nil

D It raises a NoMethodError

public_send raises a NoMethodError if the method is private.

How do you pass arguments to a method called with send?

A As a hash after the method name

B As additional parameters after the method name

C You cannot pass arguments with <code>send</code>

D Only one argument is allowed

Arguments are passed as additional parameters after the method name symbol or string.

Why might you use send instead of calling a method directly?

A To call methods dynamically when the method name is stored in a variable

B To improve performance

C To avoid syntax errors

D To make code shorter

send is useful for dynamic method calls when the method name is not known until runtime.

Explain how the send method works in Ruby and give an example of calling a method with arguments.

Think about how you can call a method when you only have its name as a string or symbol.

Describe the difference between send and public_send and when you might use each.

Consider which method respects Ruby's method visibility rules.