Hash Methods

Add a record:

[116] pry(main)> map = {}

=> {}

[117] pry(main)> map['first'] = 1

=> 1

[118] pry(main)> map

=> {"first"=>1}

Get a record:

[120] pry(main)> map['first']

=> 1

Check if contains key

[109] pry(main)> temp

=> {:third_message=>"this is third message", :fourth_message=>"this is a fourth message"}

# With has_key?

[110] pry(main)> temp.has_key?(:second_message)

=> false

[111] pry(main)> temp.has_key?(:third_message)

=> true

# With key?

[6] pry(main)> temp.key?(:second_message)

=> false

[7] pry(main)> temp.key?(:third_message)

=> true

Delete a record:

[102] pry(main)> temp

=> {:first_message=>"this is a message",

:third_message=>"this is third message",

:fourth_message=>"this is a fourth message"}

[103] pry(main)> temp.delete(:first_message)

=> "this is a message"

[104] pry(main)> temp

=> {:third_message=>"this is third message", :fourth_message=>"this is a fourth message"}

Delete all records

temp.clear

Get the length

temp.length

Access keys:

[100] pry(main)> temp.keys

=> [:first_message, :third_message, :fourth_message]

Access values:

[101] pry(main)> temp.values

=> ["this is a message", "this is third message", "this is a fourth message"]

Resources:

• https://www.shortcutfoo.com/app/dojos/ruby-hashes/cheatsheet

Related leetcode problem:

• https://leetcode.com/problems/two-sum/