[R] Removing values containing a specific character

[Uwe Ligges]

On 27.01.2013 07:11, ypodeswa wrote:
> Actually, it worked perfectly for my sample data, but my actual data has
> 5.5 million rows, and grep doesn't seem to work with over a million rows.
>   Any idea on a workaround?


It is not a matter of grep() but of available memory, I guess.
Hence try to reduce the number of copies of your data, e.g. by not 
generating an interim df2.

Best,
Uwe Ligges



>
> On Sat, Jan 26, 2013 at 9:37 PM, Yasha Podeswa <ypodeswa at gmail.com> wrote:
>
>> Awesome, thanks Arun, that's exactly what I was looking for!
>>
>>
>> On Sat, Jan 26, 2013 at 9:21 PM, arun kirshna [via R] <
>> ml-node+s789695n4656749h63 at n4.nabble.com> wrote:
>>
>>> Hi,
>>> Try this:
>>> df[]<-lapply(df,as.character)
>>> df2<-df
>>> df[,1][grep("@",df$names)]<- ""
>>> df
>>>    #names             emails
>>> #1   bob       bobj at cup.com
>>> #2   joe joesmith at gmail.com
>>> #3          craig at gmail.com
>>> #4 emily   emily2 at yahoo.com
>>> #5           jane at yahoo.com
>>>
>>> #2nd part:
>>>
>>>   df2[-grep("@",df2$names),]
>>>    names             emails
>>> #1   bob       bobj at cup.com
>>> #2   joe joesmith at gmail.com
>>> #4 emily   emily2 at yahoo.com
>>> A.K.
>>>
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