Ruby array only storing last item during collect statement

Question

I have a ruby method that queries a array through a search. From what is typed in the searchbar it appends that item to another array that shows on the screen. Below is my method:

@churches = ["UGBC", "Oak Ridge Baptist", "Calvary"]
@search_results = []


def search_for(text)
  @churches.collect do |church|
    if text == church
      @search_results << church
    end
  end
end

When the code is triggered the only object that is returned when searched is the last object in the array: "Calvary". If you search any of the other items it sends back an empty array. I have tried an each statement and a collect statement and nothing will work. How do I get it to append to the empty array with no matter what item I search on?

Working with side-effects is usually a bad idea, if besides that the operation done is not idempotent (`<<`), it's conceptually pretty bad. — tokland, Jul 18 '13 at 10:52

score 1 · Accepted Answer · answered Jul 18 '13 at 10:53

1

You are not using the right method. I think Array#select is what you need. Also you might have to do a substring check for the text.

Here is an example

text = 'Ridge'

> churches.select{|c| c.include?(text)}
#=> ["Oak Ridge Baptist"]

answered Jul 18 '13 at 10:53

Santhosh

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The select method was exactly what I was looking for. Now I can append the results into a new array every time. Thanks a lot. – Jason Milam Jul 18 '13 at 12:50

score 0 · Answer 2 · answered Jul 18 '13 at 10:46

0

What is your text value?. If you are performing text("Calvary") == church.. It matches one of the element of @churches.That @churches element alone store in @search_results. So storing last element.

answered Jul 18 '13 at 10:46

Inaccessible

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undur_gongor · Answer 3 · 2013-07-18T11:59:38.497

Your function returns the value of the last expression evaluated. That is the value of @churches.collect. That -- in turn -- is an array of the three values of the block:

search_for('UGBC')               # => [["UGBC"], nil, nil]
@search_results = []
search_for('Oak Ridge Baptist')  # => [nil, ["Oak Ridge Baptist"], nil]
@search_results = []
search_for('Calvary')            # => [nil, nil, ["Calvary"]]
@search_results = []
search_for('something else')     # => [nil, nil, nil]

The block yields nil in case of no match and @search_result with the found church appended in case of a match.

Note that your function modifies @search_results. So I reset it in order to hide the side-effects of previous runs.

An obvious fix to your function is to return @search_results:

def search_for(text)
  @search_results = []
  @churches.collect do |church|
    if text == church
      @search_results << church
    end
  end
  @search_results # or even: return @search_results
end

A better implementation returning the found element or nil is

def search_for(text)
  @churches.find { | c | c == text }
end

Ruby array only storing last item during collect statement

3 Answers3