[R] how to extract strings in any column and in any row that start with

Jeff Newmiller jdnewm|| @end|ng |rom dcn@d@v|@@c@@u@
Fri May 15 22:34:11 CEST 2020


If you want to treat your data frame as if it were a vector, then convert it to a vector before you give it to grep.

unlist(tot)

On May 15, 2020 12:24:17 PM PDT, Ana Marija <sokovic.anamarija using gmail.com> wrote:
>Hello,
>
>this command was running for more than 2 hours
>grep("E10",tot,value=T)
>and no output
>
>and this command
>df1 <- tot %>% filter_all(any_vars(grepl( '^E10', .)))
>
>gave me a subset (a data frame) of tot where ^E10
>
>what I need is just a vector or all values in tot which start with E10.
>
>Thanks
>Ana
>
>On Fri, May 15, 2020 at 12:13 PM Jeff Newmiller
><jdnewmil using dcn.davis.ca.us> wrote:
>>
>> Read about regular expressions... they are extremely useful.
>>
>> df1 <- tot %>% filter_all(any_vars(grepl( '^E10', .)))
>>
>> It is bad form not to put spaces around the <- assignment.
>>
>>
>> On May 15, 2020 10:00:04 AM PDT, Ana Marija
><sokovic.anamarija using gmail.com> wrote:
>> >Hello,
>> >
>> >I have a data frame:
>> >
>> >> dim(tot)
>> >[1] 502536   1093
>> >
>> >How would I extract from it all strings that start with E10?
>> >
>> >I know how to extract all rows that contain with E10
>> >df0<-tot %>% filter_all(any_vars(. %in% c('E10')))
>> >> dim(df0)
>> >[1] 5105 1093
>> >
>> >but I just need a vector of strings that start with E10...
>> >it would look something like this:
>> >
>> >[1] "E102" "E109" "E108" "E103" "E104" "E105" "E101" "E106" "E107"
>> >
>> >Thanks
>> >Ana
>> >
>> >______________________________________________
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>>
>> --
>> Sent from my phone. Please excuse my brevity.

-- 
Sent from my phone. Please excuse my brevity.



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