From: Justin Collins <justincollins@...>
Date: 2009-01-07T15:11:53+09:00
Subject: Re: noob question: object to string

Patrick Doyle wrote:
> On Mon, Jan 5, 2009 at 11:02 AM, Darin Ginther <
> darin.ginther@allwebleads.com> wrote:
>
>   
>> So I'm able to exercise creating my own class and returning an object
>> from that class.  I'm having trouble treating the return as an integer
>> (for the purpose of a < or > compare).. Yet another noob syntax
>> question.
>>
>>
>> compare.rb:
>>    myinitialdbcount = Dbutil.new(mydb, dbuser, dbpw, counttable,
>> leadtype)
>>    puts "Initial Count:"
>>    initialcount = myinitialdbcount.count_table{ |data| p data }
>>
>> This returns:
>> Initial Count:
>> 213912
>>
>> If I try to simply print (put) it:
>> puts myinitialdbcount.count_table{ |data| p data }
>>
>> This returns:
>> nill
>>
>> I think I need to "to_int" this object or get it into a state where I
>> can assign it to a local variable... There is something I dont
>> understand here.
>>
>> dbutil.rb:
>> def count_table
>>   dbh= DBI.connect(@mydb, @dbuser, @dbpw)
>>     sth = dbh.execute("SELECT count(*) FROM #@table where type_code =
>> #@type_code")
>>      row = sth.fetch
>>      yield row[0]
>>     sth.finish
>>    dbh.disconnect
>>  end
>>
>>     
> I don't know anything about DBI, but what do you get as output from the "p
> data" statement?
>
> Also, I noticed a problem with your dbh.execute statement: "SELECT ...
> #@table ..." probably isn't doing what you were hoping it was doing.  You
> most likely meant "SELECT ... #{@table} ...", also with "#{@type_code".
>
> hth
> --wpd
>
>   

The OP's approach works as well. It's a shortcut which can be used with 
instance variables and global variables:

irb(main):001:0> @a = "hello"
=> "hello"
irb(main):002:0> "#@a there"
=> "hello there"
irb(main):003:0> $a = "hi"
=> "hi"
irb(main):004:0> "#$a back"
=> "hi back"

-Justin