Associative array/Creation: Difference between revisions
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==[[Ruby]]== |
==[[Ruby]]== |
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[[Category:Ruby]] |
[[Category:Ruby]] |
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A hash object that returns [[nil]] for unknown keys |
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hash={} |
hash={} |
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hash[666]='devil' |
hash[666]='devil' |
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hash[666] # => 'devil' |
hash[666] # => 'devil' |
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A hash object that returns 'unknown key' for unknown keys |
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hash=Hash.new('unknown key') |
hash=Hash.new('unknown key') |
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hash[666]='devil' |
hash[666]='devil' |
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hash[666] # => 'devil' |
hash[666] # => 'devil' |
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A hash object that returns "unknown key #{key}" for unknown keys |
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hash=Hash.new{|h,k|h[k]="unknown key #{k}"} |
hash=Hash.new{|h,k|h[k]="unknown key #{k}"} |
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hash[666]='devil' |
hash[666]='devil' |
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hash[777] # => 'unknown key 777' |
hash[777] # => 'unknown key 777' |
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hash[666] # => 'devil' |
hash[666] # => 'devil' |
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===Iterate over key/value=== |
===Iterate over key/value=== |
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Create a generic mapping function that applys a callback to elements in a list: |
Create a generic mapping function that applys a callback to elements in a list: |
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==[[Ruby]]== |
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[[Category:Ruby]] |
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A hash object that returns [[nil]] for unknown keys |
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hash={} |
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hash[666]='devil' |
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hash[777] # => nil |
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hash[666] # => 'devil' |
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A hash object that returns 'unknown key' for unknown keys |
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hash=Hash.new('unknown key') |
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hash[666]='devil' |
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hash[777] # => 'unknown key' |
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hash[666] # => 'devil' |
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A hash object that returns "unknown key #{key}" for unknown keys |
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hash=Hash.new{|h,k|h[k]="unknown key #{k}"} |
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hash[666]='devil' |
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hash[777] # => 'unknown key 777' |
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hash[666] # => 'devil' |
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==[[Smalltalk]]== |
==[[Smalltalk]]== |
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