Ruby Basics
Variables, data types, control flow, methods, blocks, procs, lambdas
1What is the difference between a local variable and an instance variable in Ruby?
What is the difference between a local variable and an instance variable in Ruby?
回答
A local variable starts with a lowercase letter or underscore and is only accessible within its scope (method or block). An instance variable starts with @ and is accessible in all methods of the object, persisting throughout the instance's lifetime. This distinction is fundamental for state management in Ruby objects.
2How to declare a constant in Ruby and what is its naming convention?
How to declare a constant in Ruby and what is its naming convention?
回答
In Ruby, a constant is declared using a name starting with an uppercase letter. By convention, constants are written in SCREAMING_SNAKE_CASE (e.g., MAX_SIZE = 100). Ruby emits a warning if a constant is modified, but doesn't prevent it unlike other languages.
3What is the result of the expression 5 / 2 in Ruby and how to get a decimal result?
What is the result of the expression 5 / 2 in Ruby and how to get a decimal result?
回答
In Ruby, division between two integers (Integer) returns an integer (5 / 2 = 2). To get a decimal result, at least one operand must be a Float: 5.0 / 2 or 5 / 2.0 or 5.to_f / 2. This rule follows the integer division principle present in many languages.
What is the difference between a Symbol (:name) and a String ("name") in Ruby?
How does string interpolation work in Ruby?
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