Message-ID: <1359314200.90410.YahooMailNeo@web142602.mail.bf1.yahoo.com>
Date: 2013-01-27T19:16:40Z
From: arun
Subject: Removing values containing a specific character
In-Reply-To: <CANEe9Zrz8dd9Q4gvy70S83LpSxbFh2=VBG=hJmn0aFkBr4gg6Q@mail.gmail.com>
Hi,
I tried with bigger dataset.
set.seed(25)
names <- sample(c("bob", "joe", "craig at gmail.com", "emily", "jane at yahoo.com"),5e6,replace=TRUE)
set.seed(1651)
emails
<- sample(c("bobj at cup.com", "joesmith at gmail.com", "craig at gmail.com",
"emily2 at yahoo.com", "jane at yahoo.com"),5e6,replace=TRUE)
?df <- data.frame(names, emails)
?dim(df)
#[1] 5000000?????? 2
?df[]<-lapply(df,as.character)
?system.time(df[,1][grep("@",df$names)]<- "" )
#?? user? system elapsed
#? 1.732?? 0.108?? 1.844
?system.time(dfNew1<-df[grep("\\w+",df$names),])
#?? user? system elapsed
#? 0.896?? 0.024?? 0.923
?system.time(dfNew2<- df[df$names!="",])
#?? user? system elapsed
?# 0.460?? 0.028?? 0.490
A.K.
________________________________
From: Yasha Podeswa <ypodeswa at gmail.com>
To: arun <smartpink111 at yahoo.com>
Cc: R help <r-help at r-project.org>; Uwe Ligges <ligges at statistik.tu-dortmund.de>
Sent: Sunday, January 27, 2013 2:05 PM
Subject: Re: [R] Removing values containing a specific character
You two were 100% right, it was just a memory issue.? This was part of a bigger project where I had a number of data frames loaded, all with 1-5 million rows. Cleaned up my code to have less data frames loaded at once, and everything is working great.? Thanks for the help!
On Jan 27, 2013 9:46 AM, "arun" <smartpink111 at yahoo.com> wrote:
Hi Yasha,
>
>?I guess you got Uwe's response.
>
>?I created `df2` with the intention of getting the two results from the original dataset.
>For example, after you get the first result
>df[,1][grep("@",df$names)]<- ""
>#you can get the second result by:
>df[df$names!="",]
>?# names???????????? emails
>#1?? bob?????? bobj at cup.com
>#2?? joe joesmith at gmail.com
>#4 emily?? emily2 at yahoo.com
>
>#or
>df[grep("\\w+",df$names),]
>#? names???????????? emails
>#1?? bob?????? bobj at cup.com
>#2?? joe joesmith at gmail.com
>#4 emily?? emily2 at yahoo.com
>
>But, I am? not sure how this will work over a 5.5 million rows.
>A.K.
>
>
>
>
>----- Original Message -----
>From: ypodeswa <ypodeswa at gmail.com>
>To: r-help at r-project.org
>Cc:
>Sent: Sunday, January 27, 2013 1:11 AM
>Subject: Re: [R] Removing values containing a specific character
>
>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?
>
>
>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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