by Sai gowtham

How to check if a variable is defined in Ruby

In this tutorial, we are going to learn about how to check if a given variable is defined or not in Ruby.

Using defined? keyword

In ruby, we can use the built-in defined? keyword to check if a variable is defined or not.

The defined? keyword returns the information about the expression if a variable is defined in the current scope; otherwise, it returns nil.

Here is an example:

year = 2021

puts defined? year

Output:

"local-variable"

second example:

puts defined? day

Output:

nil

Css Tutorials & Demos

How rotate an image continuously in CSS

In this demo, we are going to learn about how to rotate an image continuously using the css animations.

How to create a Instagram login Page

In this demo, i will show you how to create a instagram login page using html and css.

How to create a pulse animation in CSS

In this demo, i will show you how to create a pulse animation using css.

Creating a snowfall animation using css and JavaScript

In this demo, i will show you how to create a snow fall animation using css and JavaScript.

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