Thanks!  Very glad you pointed me to the paste function, it looks very
helpful.

I have a quick follow-up after reading through the online tutorial on the
"paste" function:

Why do we need quotation marks around "Major Gleason" and "Minor Gleason"
in: output = paste(df [,'Major.Gleason'],  df[ ,'Minor.Gleason'], sep='+')?
The "paste" function is going to concatenate the first and second parameters
and separate them by the "+" sign, so I'm not clear why we need to put
quotation marks around the dataframe column headers...

Thanks,

Ben


On Mon, Jun 20, 2011 at 11:58 AM, David Winsemius <dwinsemius@comcast.net>wrote:

>
> On Jun 20, 2011, at 11:47 AM, Luke Miller wrote:
>
>  If we assume that your data are in a data frame (which doesn't allow
>> spaces in column names, hence the periods in the call below):
>>
>>  df = data.frame(Major.Gleason = c(4,5,2,3), Minor.Gleason = c(3,2,4,3))
>>>
>>
>> You can paste together the contents of the two columns with a plus
>> sign in between using the paste() function. The sep='' option at the
>> end of the function call specifies that no spaces should be included
>> between pasted items.
>>
>>  output = paste(as.character(df [,'Major.Gleason']), '+', as.character(df[
>>> ,'Minor.Gleason']), sep='')
>>>
>>
> I do not think the as.character is needed. Coercion to character is
> implicit in the use of paste(). And  the sep argument could be "+".
>
> output = paste(df [,'Major.Gleason'],  df[ ,'Minor.Gleason'], sep='+')
>
> --
> David.
>
>
>
>> The new object 'output' is a character vector containing the 4 strings
>> you're after:
>>
>>  print(output)
>>>
>> [1] "4+3" "5+2" "2+4" "3+3"
>>
>>
>> On Mon, Jun 20, 2011 at 11:31 AM, Ben Ganzfried <ben.ganzfried@gmail.com>
>> wrote:
>>
>>>
>>> Hi --
>>>
>>> I had a pretty quick R question since unfortunately I have not been able
>>> to
>>> find an answer on Google.  It shouldn't take much more than a minute to
>>> answer.
>>>
>>> I'm trying to add up the major gleason grade and minor gleason grade for
>>> an
>>> analysis of patients with prostate cancer.  One column has values under
>>> "Major Gleason" and another column has values under "Minor Gleason."  For
>>> example,
>>> Major Gleason     Minor Gleason
>>> 4                         3
>>> 5                         2
>>> 2                         4
>>> 3                         3
>>>
>>> I want my output to be:
>>> "4+3"
>>> "5+2"
>>> "2+4"
>>> "3+3"
>>>
>>> The quasi-pseudocode in Java is basically:
>>>
>>> major = column$majorGleason
>>> minor = column$minorGleason
>>> for item in len(Major Gleason) {
>>>  string s = major(item) "+" minor(item);
>>> }
>>> return s;
>>>
>>> But trying the same idea in R:
>>>
>>> string <- major "+" minor
>>>
>>> gives me an error: "unexpected string constant in..."
>>>
>>> I would greatly appreciate any help.
>>>
>>> Thanks,
>>>
>>> Ben
>>>
>>>       [[alternative HTML version deleted]]
>>>
>>> ______________________________**________________
>>> R-help@r-project.org mailing list
>>> https://stat.ethz.ch/mailman/**listinfo/r-help<https://stat.ethz.ch/mailman/listinfo/r-help>
>>> PLEASE do read the posting guide http://www.R-project.org/**
>>> posting-guide.html <http://www.R-project.org/posting-guide.html>
>>> and provide commented, minimal, self-contained, reproducible code.
>>>
>>
>>
>>
>> --
>> ___________________________
>> Luke Miller
>> Postdoctoral Researcher
>> Marine Science Center
>> Northeastern University
>> Nahant, MA
>> (781) 581-7370 x318
>>
>> ______________________________**________________
>> R-help@r-project.org mailing list
>> https://stat.ethz.ch/mailman/**listinfo/r-help<https://stat.ethz.ch/mailman/listinfo/r-help>
>> PLEASE do read the posting guide http://www.R-project.org/**
>> posting-guide.html <http://www.R-project.org/posting-guide.html>
>> and provide commented, minimal, self-contained, reproducible code.
>>
>
> David Winsemius, MD
> West Hartford, CT
>
>

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