Understand `nil` in Ruby

PublishedAugust 13, 2021

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Lynn Chang

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Lynn's Dev Blog

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# irb $ nil.blank? #=> Traceback (most recent call last): # 4: from /Users/yuchu/.rvm/rubies/ruby-2.6.6/bin/irb:23:in `<main>' # 3: from /Users/yuchu/.rvm/rubies/ruby-2.6.6/bin/irb:23:in `load' # 2: from /Users/yuchu/.rvm/rubies/ruby-2.6.6/lib/ruby/gems/2.6.0/gems/irb-1.0.0/exe/irb:11:in `<top (required)>' # 1: from (irb):14 #NoMethodError (undefined method `blank?' for nil:NilClass)

$ result = 'Hello' $ note = { nickname: 'Jenny' } $ result = 'Hello, Jane.' if nil $ result #=> 'Hello' $ result = 'Hello, Jane.' if false $ result #=> 'Hello' $ result = 'Hello, Jane.' if true $ result #=> 'Hello, Jane.' $ result = 'Hello, Bob.' if note[:non_existent_key] $ result #=> 'Hello, Jane.' $ result = 'Hello, Jenny.' if note[:nickname] $ result #=> 'Hello, Jenny.'

Understand `nil` in Ruby

Comments

More from this blog

Local PostgreSQL Upgrade and Database Restoration Guide

Resolving Rails Runtime Errors: A Guide to Handling Unpersisted Changes with with_lock

Upgrade to Ruby 3.0.6 (OpenSSL issues)

What’s the relationship between require, $LOAD_PATH and $LOADED_FEATURES in Ruby?

How I learned to write raw SQL

What's `nil`?

Let's play with nil now.

1. `nil` and `nil?`

2. `nil` can only respond to `blank?` in Rails.

3. `nil` and `!` , `!!` operator

4. `nil` and Ruby if modifier

Reference

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More from this blog

What's nil?

Let's play with nil now.

1. nil and nil?

2. nil can only respond to blank? in Rails.

3. nil and ! , !! operator

4. nil and Ruby if modifier

Reference

What's `nil`?

1. `nil` and `nil?`

2. `nil` can only respond to `blank?` in Rails.

3. `nil` and `!` , `!!` operator

4. `nil` and Ruby if modifier