Wat in ruby

wat.rb

nil.to_i.nil? # false
"x".to_i == 0 # true
"12xhdhsjh".to_i == 12 # true

# Rails 4
{surprise: true, 'surprise' => false}.symbolize_keys
# {:surprise => false} 

{surprise: true, 'surprise' => false}.symbolize_keys!
# {:surprise => false}

{surprise: true, 'surprise' => false}.stringify_keys
# {"surprise" => false}

{surprise: true, 'surprise' => false}.stringify_keys!
# {"surprise" => true}