Search within an array of hashes by value

gistfile1.rb

# Say you have an array of hashes. They keys can be strings or symbols,
# Ruby doesn't care much in this instance.

# And say you want to do a search based on the value of one of those hash keys.
# First, let's make a new array of hashes.

haystack = Array.new

haystack << {:title => "Privacy Status", :id => "sakai.privacy"}
haystack << {:title => "Worksite Information", :id => "sakai.iframe.site"}
haystack << {:title => "Site Setup", :id => "sakai.siteinfo"}

# Now let's try to find one of these array elements
# We'll pick an arbitrary criteria. I'm going to look
# for an :id with a specified value.

# We can use the Enumerable#select method!

result = haystack.select {|h| h[:id] == "sakai.siteinfo"}

# We can see that the result is the entire array element for that match
p result
#=> [{:title=>"Site Setup", :id=>"sakai.siteinfo"}]

p result.empty?
#=> false

# And just to verify, what happends when you don't find a match:
wrong_result = haystack.select {|h| h[:id] == "wrong.tool.id"}

p wrong_result
#=> []
p wrong_result.empty?
#=> true