Saari Development

In response to my previous post my friend Arsalan posted his C# solution on my shared friend blog SaarayDost

Both my solution and his had line numbers with the code which makes it easy to reference a line number in a discussion but if you want to run and test code it can be painful to strip them out one by one.

I wrote the following quick ruby one liner that can be run on a file after copy-pasting the code and saving it.

ruby -lne 'puts $_.gsub(/^\s?\d+:?/, "")' ali.rb > ali_fixed.rb

I am sure there good be a better more clever way to do this after all TIMTOWDI but here I use the l to remove newline at the end of each line, n to iterate over the given file one line at a time and e to execute the following code string (in quotes, on each line). $_ is the magic variable (a perl legacy in ruby) that magically populated, in this case with the current line of file being processed. gsub simply removed the pattern match in the first argument by the string in the second argument.

While searching for a good description of $_ I also found this interesting link with other useful ruby one-liners.

Update: found another way to achieve the above result. -p option prints the $_ at the end of each iteration.

ruby -lpe '$_.gsub!(/^\s?\d+:?/, "")' ali.rb > ali_fixed.rb

Question from : Blist.com Career Page

 # Without using any built in date or time functions, write a function or method
 # that accepts two mandatory arguments. The first argument is a string of the
 # format "[H]H:MM {AM|PM}" and the second argument is an integer. Assume the
 # integer is the number of minutes to add to the string. The return value of
 # the function should be a string of the same format as the first argument.
 # For example AddMinutes("9:13 AM", 10) would return "9:23 AM". The exercise
 # isn't meant to be too hard. I just want to see how you code. Feel free to
 # do it procedurally or in an object oriented way, whichever you prefer. Use
 # any language you want. Write production quality code.
 # Question Source: http://blist.com/blog/

 # the following solution was developed using TDD

 require 'test/unit'

 class TestTimeCalc < Test::Unit::TestCase

     def setup
         @time = "9:13 AM"
     end

     def test_new_time_cal
         assert_not_nil(TimeCalc.new)
     end

     def test_add_minute_zero
         assert_equal(@time, TimeCalc.add_minutes(@time, 0))
     end

     def test_add_minute_ten
         assert_equal("9:23 AM", TimeCalc.add_minutes(@time, 10))
     end

     def test_add_minute_thirteen
         assert_equal("9:26 AM", TimeCalc.add_minutes(@time, 13))
     end

     def test_add_hour
         assert_equal("10:13 AM", TimeCalc.add_minutes(@time, 60))
     end

     def test_add_two_hours_fifteen_minutes
         assert_equal("11:28 AM", TimeCalc.add_minutes(@time, 135))
     end

     def test_add_past_meridiem
         # 785 minutes = 13 hours and 5 minutes
         assert_equal("10:18 PM", TimeCalc.add_minutes(@time, 785))
     end

     def test_alpha_hour_min_format_throws_exception
         assert_raise(ArgumentError) { TimeCalc.add_minutes("AB:CD AM", 10) }
     end

     def test_bad_meridiem_throws_exception
         assert_raise(ArgumentError) { TimeCalc.add_minutes("AB:CD TM", 10) }
     end

     def test_hr_greater_than_twelve
         assert_raise(ArgumentError) { TimeCalc.add_minutes("13:00 PM", 10) }
     end

     def test_min_greater_than_fifty_nine
         assert_raise(ArgumentError) { TimeCalc.add_minutes("12:60 PM", 10) }
     end

 end # end class TestTimeCalc

 class TimeCalc

     def self.add_minutes(time, minutes)
       (hour, min, meridiem) = parse_time_string(time)

       hour_increment = (min + minutes)/60
       min_increment = (min + minutes)%60 - min
       if (hour_increment >= 12)
         meridiem = (meridiem == 'AM' ? 'PM' : 'AM')
         hour_increment -= 12
       end

       hour += hour_increment
       min += min_increment

       hour.to_s + ":" + min.to_s + " " + meridiem
     end

     private

     def self.parse_time_string(time)
         raise ArgumentError unless (matches = time.match(/(\d{1,2}):(\d{1,2})\s+(\w{2})/))
         matches = time.match(/^(\d{1,2}):(\d{1,2})\s+([A|P]M)$/)
         hour = matches[1].to_i
         min = matches[2].to_i
         meridiem = matches[3]
         raise ArgumentError unless (hour <= 12)
         raise ArgumentError unless (min < 60)
         return [hour, min, meridiem]
     end

 end # end class TimeCalc

I had seen other vim experts do this but couldn’t remember how they did. Today I finally search and found how to insert the output of a unix/linux command directly in a vim buffer(without copy-pasting).

  :r!ls /home/

or in the visual mode (by pressing V) simply !ls /home/

Simple isn’t it and quite useful at times.