[R] how to use AND in grepl

[chalabi.elahe at yahoo.de]

Yes it works, but let me explain what I am going to do. I extract all the names I want and then create a new column out of them for my plot. This is he whole thing I do:
  PD=subset(df,grepl("pd",Command)) //extract names in Command with only "pd"
  t2=subset(df,grepl("t2",Command)) //extract names with only "t2"
  PDT2=subset(df,grepl("(.*t2.*pd.*)|(.*pd.*t2.*)",df$Command) // extract names which contain both "pd" and "t2"
  v1=c('PD','t2','PDT2')// I create a vector with these conditions
  str_extract(df$Command,paste(v1,collaps='|')) //returning patterns, using stringr library

here I see no pattern named PDT2 but there are only PD and t2 patterns.
On Monday, May 2, 2016 8:18 AM, Tom Wright <tom at maladmin.com> wrote:



Sorry for the missed braces earlier. I was typing on a phone, not the best place to conjugate regular expressions.
Using the example you provided:

> df=data.frame(Command=c("_localize_PD", "_localize_tre_t2", "_abdomen_t1_seq", "knee_pd_t1_localize", "pd_local_abdomen_t2"))

> grepl("(.*t2.*pd.*)|(.*pd.*t2.*)",df$Command)
[1] FALSE FALSE FALSE FALSE  TRUE

> subset(df,grepl("(.*t2.*pd.*)|(.*pd.*t2.*)",df$Command))
              Command
5 pd_local_abdomen_t2



On Mon, May 2, 2016 at 7:42 AM, <chalabi.elahe at yahoo.de> wrote:

Thanks Peter, you were right, the exact grepl is grepl("(.*t2.*pd.*)|(.*pd.*t2.*)",df$Command), but it does not change anything in Command, when I check the size of it by sum(grepl("(.*t2.*pd.*)|(.*pd.*t2.*)",df$Command))  the result is 0, but I am sure that the size is not 0. It seems that this AND does not work.
>
>
>
>On Monday, May 2, 2016 5:05 AM, peter dalgaard <pdalgd at gmail.com> wrote:
>
>On 02 May 2016, at 12:43 , ch.elahe via R-help <r-help at r-project.org> wrote:
>
>> Thanks for your reply tom. After using  Subset(df,grepl("(.*t2.*pd.*)|(.*pd.*t2.*)"),df$Command)  I get this error: Argument "x" is missing, with no default. Actually I don't know how to fix this. Do you have any idea?
>
>Tom's code was missing a ")" but not where you put one. He probably also didn't intend to capitalize "subset".
>
>
>-pd
>
>> Thanks,
>> Elahe
>>
>>
>> On Saturday, April 30, 2016 7:35 PM, Tom Wright <tom at maladmin.com> wrote:
>>
>>
>>
>> Actually not sure my previous answer does what you wanted. Using your approach:
>> t2pd=subset(df,grepl("t2",df$Command) & grepl("pd",df$Command))
>> Should work.
>> I think the regex pattern you are looking for is:
>> Subset(df,grepl("(.* t2.*pd.* )|(.* pd.* t2.*)",df$Command)
>>
>> On Sat, Apr 30, 2016, 7:07 PM Tom Wright <tom at maladmin.com> wrote:
>>
>> subset(df,grepl("t2|pd",x$Command))
>>>
>>>
>>>
>>>
>>> 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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>>>> 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.
>>>> .
>>
>> ______________________________________________
>> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> 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.
>
>--
>Peter Dalgaard, Professor,
>Center for Statistics, Copenhagen Business School
>Solbjerg Plads 3, 2000 Frederiksberg, Denmark
>Phone: (+45)38153501
>Office: A 4.23
>Email: pd.mes at cbs.dk  Priv: PDalgd at gmail.com
>