[R] Just another pattern matching / indexing question

[Denis Kazakiewicz]

For the sake of simplicity I've made your data example 

idd	d1	d2	d3	d4
1	a	d	b	c
2	a	d	v	h
3	c	b	v	NA
4	q	v	NA	f





df <- read.table('clipboard', header = TRUE,na.strings="NA")
df

logVec <- apply(df[2:5],1,function(x)"a"%in%x) #find drug "a" from
example
df2 <- cbind(df,logVec)
df2

Good luck in your work :)

У Аўт, 08/02/2011 у 11:38 -0800, dunner піша:
> Hi all, thank you for your patience.
> 
> I am dealing with a large dataset detailing patients and medications
> 
> Medications are hard to code, as they are (usually) meaningless unless
> matched with doses.
> 
> I have a dataframe with vectors (Drug1, Drug2..... Drug 16) and individual
> patients are represented by rows.
> The vectors are actually factors, with 100s of possible levels (all the
> drugs the patient could be on).
> 
> All I want to do is produce a vector of logicals (TTTTFFFFTTT......) that I
> can cbind into the dataframe, that will tell me whether a patient is or is
> not on a particular, important drug.
> 
> This i so I can use particularly important drugs' presence or absence as
> categorical covariates in a model.
> 
> I've tried grep, to search along the rows, and I can generate a vector of
> identifiers, but I cannot seem to generate the vector of logicals.
> 
> I realise I'm doing something simply wrong.
> 
> 
> names(drugindex)
>  [1] "book.MRN" "DRUG1"    "DRUG2"    "DRUG3"    "DRUG4"    "DRUG5"   
>  [7] "DRUG6"    "DRUG7"    "DRUG8"    "DRUG9"    "DRUG10"   "DRUG11"  
> [13] "DRUG12"   "DRUG13"   "DRUG14"   "DRUG15"   "DRUG16"  
> 
> > truvec<-drugindex$book.MRN[as.vector(unlist(apply(drugindex[,2:17], 2,
> > grep, pattern="Lamotrigine")))]
> > truvec
> truvec
> [1] 0024633  0008291  0008469  0030599  0027667 
> 37 Levels: 0008291  0008469  0010188  0014217  0014439  0015822  ... 0034262 
> 
> > head(drugindex)
>    book.MRN       DRUG1        DRUG2          DRUG3        DRUG4       
> DRUG5
> 4  0008291  Venlafaxine Procyclidine  Flunitrazepam Amisulpiride   
> Clozapine
> 31 0008469  Venlafaxine  Mirtazapine        Lithium   Olanzapine  
> Metoprolol
> 3  0010188   Flurazepam    Valproate     Olanzapine  Mirtazapine
> Esomeprazole
> 13 0014217      Aspirin     Ramipril Zuclopenthixol    Lorazepam 
> Haloperidol
> 15 0014439    Zopiclone     Diazepam    Haloperidol  Paracetamol        
> <NA>
> 5  0015822   Olanzapine  Venlafaxine        Lithium  Haloperidol  
> Alprazolam
>          DRUG6      DRUG7      DRUG8      DRUG9          DRUG10 DRUG11
> DRUG12
> 4  Lamotrigine Alprazolam    Lithium Alprazolam            <NA>   <NA>  
> <NA>
> 31 Lamotrigine   Ramipril Alprazolam   Zolpidem Trifluoperazine   <NA>  
> <NA>
> 3  Paracetamol Alprazolam Citalopram       <NA>            <NA>   <NA>  
> <NA>
> 13        <NA>       <NA>       <NA>       <NA>            <NA>   <NA>  
> <NA>
> 15        <NA>       <NA>       <NA>       <NA>            <NA>   <NA>  
> <NA>
> 5         <NA>       <NA>       <NA>       <NA>            <NA>   <NA>  
> <NA>
>    DRUG13 DRUG14 DRUG15 DRUG16
> 4    <NA>   <NA>   <NA>   <NA>
> 31   <NA>   <NA>   <NA>   <NA>
> 3    <NA>   <NA>   <NA>   <NA>
> 13   <NA>   <NA>   <NA>   <NA>
> 15   <NA>   <NA>   <NA>   <NA>
> 5    <NA>   <NA>   <NA>   <NA>
> 
> And what I want is a vector of logicals for  each drug, saying whether that
> patient is on it 
> 
> Thank you all for your time.
> 
> Ross Dunne MRCPsych
> 
> 
> 
> 
> 
>