# Ruby and Excel Issue

**URL:** <https://www.ruby-forum.com/t/ruby-and-excel-issue/155857>\
**Category:** wxRuby\
**Created:** [December 17, 2008, 5:33pm UTC](https://www.ruby-forum.com/t/ruby-and-excel-issue/155857 "2008-12-17T17:33:35Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![sweatje](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/ad7895/32.png) [@sweatje](https://www.ruby-forum.com/u/sweatje)\
**Post date:** [December 17, 2008, 5:33pm UTC](https://www.ruby-forum.com/t/ruby-and-excel-issue/155857/1 "2008-12-17T17:33:35Z")

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All,

It seems that Ruby has a problem with using variables in certain  
scenarios. Previously, I was passing a parameter to a class named  
‘Test’ with a function in it named ‘go’. This is the syntax that I  
used, Test.new.go(‘hello’) The function ‘go’ would open a .xls file  
with the parameter in the path, such as C:\hello\data.xls. Everything  
was working fine then. Now, instead of using the actual string ‘hello’  
as the parameter, I am using an array element variable, so the syntax is  
Test.new.go(array[x]). Now the ‘go’ function throws the '‘File not  
found’ error. In the error message, both the path and file are correct,  
so I do not understand why the file cannot be found. Does anyone have  
any idea about what could be going on? Thanks in advance for any help.

- Shelton

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<div class="post-metadata">

**Author:** ![sweatje](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/ad7895/32.png) [@sweatje](https://www.ruby-forum.com/u/sweatje)\
**Post date:** [December 17, 2008, 7:00pm UTC](https://www.ruby-forum.com/t/ruby-and-excel-issue/155857/2 "2008-12-17T19:00:28Z")

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Hi

I wasn’t clear this was a question about wxRuby, or just a general Ruby  
question. If it’s the latter, it’s better directed to comp.lang.ruby  
newsgroup / ruby-talk mailing list.

Jason S. wrote:

> It seems that Ruby has a problem with using variables in certain  
> scenarios.

Don’t take this the wrong way - but if Ruby had a defect by which it  
randomly changed the value of variables under your nose, someone would  
probably have run into it before and reported it…

> Previously, I was passing a parameter to a class named ‘Test’ with a  
> function in it named ‘go’. This is the syntax that I used,  
> Test.new.go(‘hello’) The function ‘go’ would open a .xls file with  
> the parameter in the path, such as C:\hello\data.xls. Everything was  
> working fine then. Now, instead of using the actual string ‘hello’ as  
> the parameter, I am using an array element variable, so the syntax is  
> Test.new.go(array[x]). Now the ‘go’ function throws the '‘File not  
> found’ error. In the error message, both the path and file are  
> correct, so I do not understand why the file cannot be found.

Hard to know what might be going on without sight of the code. There  
_must_ be some difference between the literal string ‘hello’ and the  
array element.

Things to suspect are: the array index ‘x’ doesn’t point to a valid  
member; the input value array[x] is not what you expect - perhaps it  
contains spaces or newlines or wrong-case characters so that it doesn’t  
stand out as wrong; the ‘go’ method is altering the parameter in some  
unanticipated way.

I would recommend writing some tests for your class, so you can verify  
your assumptions about how that class works with different input. Give  
it both correct and incorrect input parameters, to check that it works  
in the first case and fails gracefully in the second. Writing tests can  
also help structure your code better; specifically to GUI code, it can  
help identify where too much application logic is being moved into the  
GUI layer. There are numerous testing frameworks for ruby; personally I  
find ‘test/unit’, included by default with Ruby, does everything I need,  
but you may wish to explore other options (eg rspec).

hth  
a