From: Ben Gribaudo <rubytalk@...>
Date: 2005-06-16T01:49:25+09:00
Subject: Unexpected sprintf/String % Behavior

Hello,

I am puzzled by some strange (to me) behavior exhibited by String's % 
method as well as sprintf. Both "%02d" % "07" and sprintf("%02d","07") 
output "07". However, "%02d" % "08" and sprintf("%02d","08") both raise 
'ArgumentError: invalid value for Integer: "08"'. Why does a string of 
"07" work while "08" does not?

This is true when I test this on a MS Windows XP Pro box running Ruby 
1.6.8 and when I test it on a Debian Woody box (kernal 2.4.19) running 
Ruby 1.8.2. IRB examples and results are below.

Thank you,
Ben

Win XP box
-------------
irb(main):014:0> "%02d" % "07"
=> "07"
irb(main):015:0> "%02d" % "08"
ArgumentError: invalid value for Integer: "08"
        from (irb):15:in `%'
        from (irb):15
irb(main):017:0> sprintf("%02d","07")
=> "07"
irb(main):018:0> sprintf("%02d","08")
ArgumentError: invalid value for Integer: "08"
        from (irb):18:in `sprintf'
        from (irb):18

Linux box
----------
irb(main):003:0> "%02d" % "07"
=> "07"
irb(main):004:0> "%02d" % "08"
ArgumentError: invalid value for Integer: "08"
        from (irb):4:in `%'
        from (irb):4

irb(main):005:0> sprintf("%02d","07")
=> "07"
irb(main):006:0> sprintf("%02d","08")
ArgumentError: invalid value for Integer: "08"
        from (irb):6:in `sprintf'
        from (irb):6