Ruby Checking if string contains substring

Question

I have many log files, each contains a line like this one:

THIS LINE IS DIFFERENT CASE_WINDOWS_TEST_00 PASSED

I'm searching if line contains "_XXX_TEST_" string. I created a hash:

@@groups = {
    "_LINUX_TEST_" => "Linux_tests",
    "_WINDOWS_TEST_" => "Windows_tests"
}

To check if the line contains a substring (a key from @@groups) I implemented method get_group_name which returns a value from @@groups.

def get_group_name(searchLine)
    @@groups.keys.each do |i| 
        if searchLine.include? i
            return @@groups[i]
        end
    end
end

It works fine, returns proper values. I use this method in another method that iterates through log file.

def get_group_name_from_file(fileName)
    # fileName - filename or path to the file.txt
    file = File.open(fileName)
    while (line = file.gets)
        found = get_group_name(line)
        if found 
            return found
        end
    end
end

And here is the problem. Method get_group_name_from_file returns list of keys from @@groups hash instead of one string (a value from that hash).

can't reproduce

Sergio Tulentsev
– Sergio Tulentsev

2016-09-28 08:16:21 +00:00
Commented Sep 28, 2016 at 8:16 — Sergio Tulentsev
– Sergio Tulentsev, Commented Sep 28, 2016 at 8:16

Anuja · Accepted Answer · 2016-09-28 08:22:39Z

1

It happens when it returns the output returned by each method if control doesn't reach upto:

return @group[i];

You can update method as:

def get_group_name(searchLine)
  @@groups.keys.each do |i| 
    if searchLine.include? i
      return @@groups[i]
    end
  end
  return nil
end

One more option:

def get_group_name(searchLine)
  @groups.keys.detect do |i|
    if searchLine.include? i
      return @groups[i]
    end
  end
end

edited Sep 28, 2016 at 8:22

answered Sep 28, 2016 at 8:17

Anuja

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4 Comments

Anuja Over a year ago

One more option: def get_group_name(searchLine) @groups.keys.detect do |i| if searchLine.include? i return @groups[i] end end end

Sergio Tulentsev Over a year ago

if we use detect, we don't need if or return

Anuja Over a year ago

We need it because iteration is over the keys and not value. So it will return key but we want value.

Sergio Tulentsev Over a year ago

Ah, right. In this case, this is a very bad usage of detect, I think. You only use it for its implicit nil return value (if nothing found). Misleading. I like the first one better. :)

Oleksandr Holubenko · Accepted Answer · 2016-09-28 08:50:08Z

1

I think, this problem could appear when your log file doesn't have lines that include any of your @@groups.keys, so for solve this problem, you can add this lines:

@@groups = {
    "_LINUX_TEST_" => "Linux_tests",
    "_WINDOWS_TEST_" => "Windows_tests"
  }

  def get_group_name(searchLine)
    @@groups[@@groups.keys.find { |key| searchLine.include? key }]
  end

  def get_group_name_from_file(fileName)
    # fileName - filename or path to the file.txt
    file = File.open(fileName)
    while (line = file.gets)
      found = get_group_name(line)
      return found if found
    end
  end

edited Sep 28, 2016 at 8:50

answered Sep 28, 2016 at 8:12

Oleksandr Holubenko

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3 Comments

Sergio Tulentsev Over a year ago

Your guess is correct, I think, but it's the other method that should be fixed.

Oleksandr Holubenko Over a year ago

@SergioTulentsev try No:2 :)

Sergio Tulentsev Over a year ago

Nope, get_group_name returns key, not value.

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