Module: MiniFacet::Extract

Defined in:
lib/mini_facet/hash/extract.rb

Instance Method Summary collapse

Instance Method Details

#extract(*args, &block) ⇒ Object

Hash#extract() => Hash Hash#extract{|k,v| predicate } => Hash Hash#extract(proc) => Hash

Returns a new Hash that contains only the k,v pairs where the k was specified in the keys array. If any k in keys is not present in the original Hash, it’s simply not the resulting Hash.

This is very useful to check that a Hash contains at least some desired keys or to get a sanitized Hash out of the one we currently have.

Examples:

h = {:bob=>'Marley',:mom=>'Barley'}
h.extract([:bob])            #=> {:bob=>'Marley'}
h.extract([:bob, :mom])      #=> {:bob=>'Marley',:mom=>'Barley'}
h.extract([:sos])            #=> {}

h.extract{|k,v| v =~ /Mar/}  #=>{:bob=>'Marley}



22
23
24
25
26
27
28
29
30
31
32
33
34
 
# File 'lib/mini_facet/hash/extract.rb', line 22

def extract(*args, &block)
  # Despide the *args, extract doesn't accept a splatted array.
  # It's really either an array or some form of block/proc.
  if block_given?
    extract_block(&block)
  elsif args[0].is_a? Proc
    extract_block(&args[0])
  elsif args[0].is_a? Array
    extract_keys(args[0])
  else
    raise ArgumentError, "extract requires either an array of keys, a block or a proc"
  end
end