43 lines
1.1 KiB
Markdown
43 lines
1.1 KiB
Markdown
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---
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title: Ruby Hash
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---
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## Ruby Hash
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A hash represents a collection of distinct key, value pairs. It is also called associative arrays. To create a hash in Ruby , use curly brackets and separate each key-value pair with comma.
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```ruby
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my_hash = {:key1 => "value", :key2 => "value2"}
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```
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You can create a hash in the following ways
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```ruby
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my_hash = Hash.new # with empty hash
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my_hash = {:key1 => "value", :key2 => "value2"} # with key's and value's defined
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```
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You can access the value of key in a hash with square brackets and key references
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```ruby
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my_hash[:key1] # value
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my_hash[:key2] # value2
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```
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You can assign a new key and value for an already defined hash
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```ruby
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my_hash[:key3] = "value3" # {:key1=>"value", :key2=>"value2", :key3=>"value3"}
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```
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You can check how many elements a hash has with the `length` method:
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```ruby
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my_hash.length # 2
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```
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You can also create integers as hash key but the syntax is different from the usual one
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```ruby
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my_hash = {1: "value"} # will raise an exception
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my_hash = {1 => "value"} # will create hash with corresponding key value pair
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```
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