[R] Help using Cast (Text) Version
David Winsemius
dwinsemius at comcast.net
Mon Jan 18 16:56:16 CET 2010
On Jan 18, 2010, at 10:26 AM, Steve Sidney wrote:
> David
>
> Excellent !!!!! It its exactly what I was looking for.
>
> Two very small questions to conclude
> 1) I don't understand the significance of the -1 in the sq brackets.
It removes the first column from the object that is offered to
apply(). I didn't think it would not have made any sense to offer the
vector of text entries, but now that I think about it again, it would
have given you a total count as a check, I suppose. Read up on
"negative indexing".
?"["
> 2) Not sure I really understand how function(x)works in this context.
The apply function with a "2" argument takes individual columns of
matrices, arrays or data.frames and offers them to the function that
follows. In this case each successive column temporally becomes "x"
and then the body of that function works on "x" and returns a value
for the sum of the !is.na() values, i.e. the count of the non-missing
entries in that column.
>
> If you can point me towards a doc that explains this in simple terms
> I would be obliged. Don't expect you to have to provide the answer.
Any of the introductory texts should explain the various forms of
indexing and the use of the apply family of functions. They are both
central to effective R programming.
--
David
>
> Once again many thanks for your patience and help
>
> Regards
> Steve
>
> ----- Original Message ----- From: "David Winsemius" <dwinsemius at comcast.net
> >
> To: "David Winsemius" <dwinsemius at comcast.net>
> Cc: "Steve Sidney" <sbsidney at mweb.co.za>; <r-help at r-project.org>
> Sent: Monday, January 18, 2010 3:58 PM
> Subject: Re: [R] Help using Cast (Text) Version
>
>
>>
>> On Jan 18, 2010, at 8:53 AM, David Winsemius wrote:
>>
>>>
>>> On Jan 18, 2010, at 7:58 AM, Steve Sidney wrote:
>>>
>>>> Hi David
>>>>
>>>> Thanks for your patience, as well as thanks to Dennis Murphy and
>>>> James Rome for trying to help.
>>>>
>>>> I have tried all your suggestions but still no joy.
>>>>
>>>> In order to try and resolve the problem I am attaching the
>>>> following files, hope the system allows this.
>>>>
>>>> 1) Test_data_res.txt (used dput and this is all the data to be
>>>> evaluated )
>>>> 2) Test_data_b.txt ( after performing the melt-cast. See the code)
>>>> 3) Annual Results NLA WMS Ver1.r ( the code for one of the
>>>> parameters to be evaluated. In this case SPC)
>>>>
>>>> Background; the data is from a laboratory Proficiency Testing
>>>> Scheme and the z-scores outside the |3| range, are identified as
>>>> "fails". My code assigns a 1 or 0 depending on this evaluation
>>>> and because not every lab participates in every round NA are
>>>> assigned where there are no results.
>>>>
>>>> What I am looking for is the following for each round (1-6)
>>>> a) The total number of participants which in this case are
>>>> represented by 1's and 0' per round
>>>
>>> > apply(b[,-1], 2, function(x) sum(is.na(x) ) )
>>> [1] 32 21 21 18 14 15
>>
>> Ooops, forgot the negation operator to turn not(NA) into TRUE:
>>
>> > apply(b[,-1], 2, function(x) sum(!is.na(x) ) )
>> [1] 40 51 51 54 58 57
>>
>>>
>>>
>>>
>>>> b) The total number of 1's, ie Fails per round
>>>
>>> > apply(b[,-1], 2, sum, na.rm=TRUE )
>>> [1] 5 2 4 3 5 7
>>>
>>>>
>>>>
>>>>
>>>> Regards
>>>> Steve
>>>>
>>>>
>>>>
>>>> ----- Original Message ----- From: "David Winsemius" <dwinsemius at comcast.net
>>>> >
>>>> To: "Steve Sidney" <sbsidney at mweb.co.za>
>>>> Cc: <r-help at r-project.org>
>>>> Sent: Monday, January 18, 2010 12:38 AM
>>>> Subject: Re: [R] Help using Cast (Text) Version
>>>>
>>>>
>>>>>
>>>>> On Jan 17, 2010, at 4:37 PM, Steve Sidney wrote:
>>>>>
>>>>>> Well now I am totally baffled !!!!!!!!!!
>>>>>>
>>>>>> Using
>>>>>>
>>>>>> sum( !is.na(b[,3])) I get the total of all col 3 except those
>>>>>> that are NA -
>>>>>> Great solves the first problem
>>>>>>
>>>>>> What I can't seem to do is use the same logic to count all the
>>>>>> 1's in that
>>>>>> col, which are there before I use the cast with margins.
>>>>>>
>>>>>> So it seems to me that somehow is wrong and is the part of my
>>>>>> understanding that's missing.
>>>>>>
>>>>>> My guess is that that before using margins and sum in the cast
>>>>>> statement the col is a character type and in order for == 1 to
>>>>>> work I need to convert this to an integer.
>>>>>
>>>>> Yiu can test your theory with:
>>>>>
>>>>> sum(as.integer(b[,3]) == 1)
>>>>>
>>>>> Or you could post some reproducible data using dput ....
>>>>>
>>>>> --
>>>>> David.
>>>>>
>>>>>
>>>>>>
>>>>>> Hope this helps you to understand the problem.
>>>>>>
>>>>>> Regards
>>>>>> Steve
>>>>>>
>>>>>> Your help is much appreciated
>>>>>> ----- Original Message ----- From: "David Winsemius" <dwinsemius at comcast.net
>>>>>> >
>>>>>> To: "Steve Sidney" <sbsidney at mweb.co.za>
>>>>>> Cc: <r-help at r-project.org>
>>>>>> Sent: Sunday, January 17, 2010 7:36 PM
>>>>>> Subject: Re: [R] Help using Cast (Text) Version
>>>>>>
>>>>>>
>>>>>>>
>>>>>>> On Jan 17, 2010, at 11:56 AM, Steve Sidney wrote:
>>>>>>>
>>>>>>>> David
>>>>>>>>
>>>>>>>> Thanks, I'll try that......but no what I need is the total
>>>>>>>> (1's) for
>>>>>>>> each of the rows, labelled 1-6 at the top of each col in the
>>>>>>>> table
>>>>>>>> provided.
>>>>>>>
>>>>>>> Part of my confusion with your request (which remains
>>>>>>> unaddressed) is
>>>>>>> what you mean by "valid". The melt-cast operation has turned a
>>>>>>> bunch of
>>>>>>> NA's into 0's which are now indistinguishable from the
>>>>>>> original 0's. So I
>>>>>>> don't see any way that operating on "b" could tell you the
>>>>>>> numbers you
>>>>>>> are asking for. If you were working on the original data,
>>>>>>> "res", you
>>>>>>> might have gotten the column-wise "valid" counts of column 2
>>>>>>> with
>>>>>>> something like:
>>>>>>>
>>>>>>> sum( !is.na(res[,2]) )
>>>>>>>
>>>>>>>>
>>>>>>>> What I guess I am not sure of is how to identify the col
>>>>>>>> after the melt
>>>>>>>> and cast.
>>>>>>>
>>>>>>> The cast object represents columns as a list of vectors. The
>>>>>>> i- th column
>>>>>>> is b[[i]] which could be further referenced as a vector. So
>>>>>>> the j- th row
>>>>>>> entry for the i-th column would be b[[i]][j].
>>>>>>>
>>>>>>>
>>>>>>>>
>>>>>>>> Steve
>>>>>>>>
>>>>>>>> ----- Original Message ----- From: "David Winsemius"
>>>>>>>> <dwinsemius at comcast.net
>>>>>>>> >
>>>>>>>> To: "Steve Sidney" <sbsidney at mweb.co.za>
>>>>>>>> Cc: <r-help at r-project.org>
>>>>>>>> Sent: Sunday, January 17, 2010 4:39 PM
>>>>>>>> Subject: Re: [R] Help using Cast (Text) Version
>>>>>>>>
>>>>>>>>
>>>>>>>>>
>>>>>>>>> On Jan 17, 2010, at 5:31 AM, Steve Sidney wrote:
>>>>>>>>>
>>>>>>>>>> Sorry to repeat the meassage, not sure if the HTML version
>>>>>>>>>> has been
>>>>>>>>>> received - Apologies for duplication
>>>>>>>>>>
>>>>>>>>>> Dear list
>>>>>>>>>>
>>>>>>>>>> I am trying to count the no of occurances in a column of
>>>>>>>>>> a data frame
>>>>>>>>>> and there is missing data identifed by NA.
>>>>>>>>>>
>>>>>>>>>> I am able to melt and cast the data correctly as well as
>>>>>>>>>> sum the
>>>>>>>>>> occurances using margins and sum.
>>>>>>>>>>
>>>>>>>>>> Here are the melt and cast commands
>>>>>>>>>>
>>>>>>>>>> bw = melt(res, id=c("lab","r"), "pf_zbw")
>>>>>>>>>> b = cast(bw, lab ~ r, sum, margins = T)
>>>>>>>>>>
>>>>>>>>>> Sample Data (before using sum and margins)
>>>>>>>>>>
>>>>>>>>>> lab 1 2 3 4 5 6
>>>>>>>>>> 1 4er66 1 NA 1 0 NA 0
>>>>>>>>>> 2 4gcyi 0 0 1 0 0 0
>>>>>>>>>> 3 5d3hh 0 0 0 NA 0 0
>>>>>>>>>> 4 5d3wt 0 0 0 0 0 0
>>>>>>>>>> .
>>>>>>>>>> . lines deleted to save space
>>>>>>>>>> .
>>>>>>>>>> 69 v3st5 NA NA 1 NA NA NA
>>>>>>>>>> 70 a22g5 NA 0 NA NA NA NA
>>>>>>>>>> 71 b5dd3 NA 0 NA NA NA NA
>>>>>>>>>> 72 g44d2 NA 0 NA NA NA NA
>>>>>>>>>>
>>>>>>>>>> Data after using sum and margins
>>>>>>>>>>
>>>>>>>>>> lab 1 2 3 4 5 6 (all)
>>>>>>>>>> 1 4er66 1 0 1 0 0 0 2
>>>>>>>>>> 2 4gcyi 0 0 1 0 0 0 1
>>>>>>>>>> 3 5d3hh 0 0 0 0 0 0 0
>>>>>>>>>> 4 5d3wt 0 0 0 0 0 0 0
>>>>>>>>>> 5 6n44r 0 0 0 0 0 0 0
>>>>>>>>>> .
>>>>>>>>>> .lines deleted to save space
>>>>>>>>>> .
>>>>>>>>>> 70 a22g5 0 0 0 0 0 0 0
>>>>>>>>>> 71 b5dd3 0 0 0 0 0 0 0
>>>>>>>>>> 72 g44d2 0 0 0 0 0 0 0
>>>>>>>>>> 73 (all) 5 2 4 3 5 7 26
>>>>>>>>>>
>>>>>>>>>> Uisng length just tells me how many total rows there are.
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>> What I need to do is count how many rows there is valid
>>>>>>>>>> data, in this
>>>>>>>>>> case either a one (1) or a zero (0) in b
>>>>>>>>>
>>>>>>>>> I'm guessing that you mean to apply that test to the column
>>>>>>>>> in b
>>>>>>>>> labeled "(all)" . If that's the case, then something like
>>>>>>>>> (obviously
>>>>>>>>> untested):
>>>>>>>>>
>>>>>>>>> sum( b$'(all)' == 1 | b$'(all)' == 0)
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> I have a report to construct for tomorrow Mon so any help
>>>>>>>>>> would be
>>>>>>>>>> appreciated
>>>>>>>>>>
>>>>>>>>>> Regards
>>>>>>>>>> Steve
>>>>>>>>>
>>>>>>>>> David Winsemius, MD
>>>>>>>>> Heritage Laboratories
>>>>>>>>> West Hartford, CT
>>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>> David Winsemius, MD
>>>>>>> Heritage Laboratories
>>>>>>> West Hartford, CT
>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>> David Winsemius, MD
>>>>> Heritage Laboratories
>>>>> West Hartford, CT
>>>>>
>>>> <Test_data_b.txt><Test_data_res.txt><Annual Results NLA WMS Ver1.r>
>>>
>>> David Winsemius, MD
>>> Heritage Laboratories
>>> West Hartford, CT
>>>
>>> ______________________________________________
>>> R-help at r-project.org mailing list
>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>>
>> David Winsemius, MD
>> Heritage Laboratories
>> West Hartford, CT
>
David Winsemius, MD
Heritage Laboratories
West Hartford, CT
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