Hidden Features

• 16

  JUL
  2006

  String Has Other Methods Besides =~/match() and sub()

  Ask anyone who knows me and they will tell you I'm a huge fan of regular expressions. I use them all the time and my FasterCSV library is a regular expression powered parser. However, even I know they are not for everything, and lately I keep running into almost comical examples of misuse. Here are some of my favorites.

  First, we have:

  str =~ /=/
  

  That snippet is like calling for a military escort (the regular expression engine) to see you safely to the grocery store down the block. That's fun, but probably overkill. In this case, a call to include?() will do the trick:

  str.include?("=")
  

  That may be more like riding your bike to the grocery store, but it gets the job done and is a bit faster to boot.

  Funny example number two. I've seen this before:

  str =~ /\Aquit\Z/
  

  Again, the regular expression engine appreciates the love, but you really just want ==:

  str == "quit"
  

  Even for some of the fancier stuff, you don't need a full blown regular expression. For example, this:

  Read more…

  In: Early Steps | Tags: Hidden Features | 3 Comments

• 8

  JUL
  2006

  The Books are Wrong About Logger

  I've read several books that introduced the standard Logger library and they all agree on one thing: you can't customize the output. That's so last version in thinking! Behold…

  Here's a trivial Logger script, showing basic functionality:

  #!/usr/bin/env ruby -w
  
  require "logger"
  
  def expensive_error_report
    sleep 3  # Heavy Computation Simulation (patent pending)
    "YOU BROKE IT!"
  end
  
  log       = Logger.new(STDOUT)
  log.level = Logger::INFO  # set out output level above the DEBUG default
  
  log.debug("We're not in the verbose debug mode.")
  log.info("We do see informative logs though.")
  if log.error?  # check that this will be printed, before waste time
    log.error(expensive_error_report)
  end
  

  If you run that you will see:

  I, [2006-07-08T11:17:19.531943 #340]  INFO -- : We do see informative logs though.
  E, [2006-07-08T11:17:22.532424 #340] ERROR -- : YOU BROKE IT!
  

  Now everyone has always known you can format the date and time display using a strftime() compatible pattern:

  #!/usr/bin/env ruby -w
  
  require "logger"
  
  def expensive_error_report
    sleep 3
    "YOU BROKE IT!"
  end
  
  log                 = Logger.new(STDOUT)
  log.level           = Logger::INFO
  log.datetime_format = "%Y-%m-%d %H:%M "  # simplify time output
  
  log.debug("We're not in the verbose debug mode.")
  log.info("We do see informative logs though.")
  if log.error?
    log.error(expensive_error_report)
  end
  

  Read more…

  In: The Standard Library | Tags: Hidden Features | 7 Comments