[R] how to use AND in grepl

[William Dunlap]

Your code looks fine to me.  What did t2pd look like?

I tried reproducing the problem in R-3.2.4(Revised) and everything worked
(although the output of str() looked a bit different - perhaps you have an
old version of R)

> df <- data.frame(TE=1:10, TR=101:110,
Command=c("pd_local_abdomen_t2","knee_pd_t1_localize","PD_localize_tre_t2","t2_localize_PD")[rep(1:4,len=10)])
> str(df)
'data.frame':   10 obs. of  3 variables:
 $ TE     : int  1 2 3 4 5 6 7 8 9 10
 $ TR     : int  101 102 103 104 105 106 107 108 109 110
 $ Command: Factor w/ 4 levels "knee_pd_t1_localize",..: 2 1 3 4 2 1 3 4 2 1
> subset(df,grepl("t2",Command) & grepl("pd",Command))
  TE  TR             Command
1  1 101 pd_local_abdomen_t2
5  5 105 pd_local_abdomen_t2
9  9 109 pd_local_abdomen_t2
> subset(df,grepl("t2",Command,ignore.case=TRUE) &
grepl("pd",Command,ignore.case=TRUE))
  TE  TR             Command
1  1 101 pd_local_abdomen_t2
3  3 103  PD_localize_tre_t2
4  4 104      t2_localize_PD
5  5 105 pd_local_abdomen_t2
7  7 107  PD_localize_tre_t2
8  8 108      t2_localize_PD
9  9 109 pd_local_abdomen_t2


Bill Dunlap
TIBCO Software
wdunlap tibco.com

On Sat, Apr 30, 2016 at 2:38 PM, ch.elahe via R-help <r-help at r-project.org>
wrote:

> Hi all,
>
> I have one factor variable in my df and I want to extract the names from
> it which contain both "t2" and "pd":
>
>   'data.frame': 36919 obs. of 162 variables
>    $TE                :int 38,41,11,52,48,75,.....
>    $TR                :int 100,210,548,546,.....
>    $Command          :factor W/2229 levels
> "_localize_PD","_localize_tre_t2","_abdomen_t1_seq","knee_pd_t1_localize","pd_local_abdomen_t2"...
>
> I have tried this but I did not get result:
>
>   t2pd=subset(df,grepl("t2",Command) & grepl("pd",Command))
>
>
> does anyone know how to apply AND in grepl?
>
> Thanks
> Elahe
>
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