R help - Jan 2014 - Performing same steps on multiple dataframes using a loop - vijay

I have three data frames df.1, df.2 and df.3. All have the same structure I.e
here is df.1

Name                    network             speed
Atlanta_Ga.           LTE.                    10
Hartford_CT.          HSPA.                  4
Seattle_WA.           LTE.                     12

I want to perform a couple of steps on each data frame and store the transformed
dataframes as df.1cleaned, df.2cleaned etc......

Here are the steps to perform. 

1.Create a new column named state, given by the last two letters of the name
field
2. Only keep rows where network is HSPA
3. Multiple the speed column by 1000

So df.1cleaned would look like
Name                Network.       Speed.     State
Hartford_CT.     HSPA.           10000.      CT

Can someone help me come up with a loop or a function that loops through all
dataframes and produces all three dataframes

Thanks
Vijay


Sent from my iPad

Hi,
Try:
df.1 <- read.table(text="Name??????????????????? network???????????
speed
Atlanta_Ga.????????? LTE.??????????????????? 10
Hartford_CT.????????? HSPA.????????????????? 4
Seattle_WA.????????? LTE.???????????????????
12",sep="",header=TRUE,stringsAsFactors=FALSE)

df.1cleaned <- within(df.1,{ state
<-gsub(".*\\_(.*)\\.$","\\1",Name);speed <-
speed*1000})
?subset(df.1cleaned,network=="HSPA.") #check your number in speed
column
#????????? Name network speed state
#2 Hartford_CT.?? HSPA.? 4000??? CT

You could use ?lapply() for multiple dataframes
df.2 <- df.1
res <- lapply(list(df.1,df.2),function(x) {x1 <- within(x,{state <-
gsub(".*\\_(.*)\\.$","\\1",Name); speed <-
speed*1000});subset(x1,network=="HSPA.")})
?names(res) <-
paste0(c("df.1","df.2"),"cleaned")

res$df.2cleaned

A.K.




On Saturday, January 18, 2014 1:39 AM, Vijay <vijaychowdhari at gmail.com>
wrote:
I have three data frames df.1, df.2 and df.3. All have the same structure I.e
here is df.1

Name? ? ? ? ? ? ? ? ? ? network? ? ? ? ? ?  speed
Atlanta_Ga.? ? ? ? ?  LTE.? ? ? ? ? ? ? ? ? ? 10
Hartford_CT.? ? ? ? ? HSPA.? ? ? ? ? ? ? ? ? 4
Seattle_WA.? ? ? ? ?  LTE.? ? ? ? ? ? ? ? ? ?  12

I want to perform a couple of steps on each data frame and store the transformed
dataframes as df.1cleaned, df.2cleaned etc......

Here are the steps to perform. 

1.Create a new column named state, given by the last two letters of the name
field
2. Only keep rows where network is HSPA
3. Multiple the speed column by 1000

So df.1cleaned would look like
Name? ? ? ? ? ? ? ? Network.? ? ?  Speed.? ?  State
Hartford_CT.? ?  HSPA.? ? ? ? ?  10000.? ? ? CT

Can someone help me come up with a loop or a function that loops through all
dataframes and produces all three dataframes

Thanks
Vijay


Sent from my iPad
______________________________________________
R-help at r-project.org mailing list
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.

Is this homework? Most of us object to doing homework here.

If not, have you gone through any R tutorials? This looks like pretty
basic stuff, and one has to wonder if you can't do this, why are you
using R at all?

Cheers,
Bert

Bert Gunter
Genentech Nonclinical Biostatistics
(650) 467-7374

"Data is not information. Information is not knowledge. And knowledge
is certainly not wisdom."
H. Gilbert Welch




On Fri, Jan 17, 2014 at 8:46 PM, Vijay <vijaychowdhari at gmail.com>
wrote:
> I have three data frames df.1, df.2 and df.3. All have the same structure
I.e here is df.1
>
> Name                    network             speed
> Atlanta_Ga.           LTE.                    10
> Hartford_CT.          HSPA.                  4
> Seattle_WA.           LTE.                     12
>
> I want to perform a couple of steps on each data frame and store the
transformed dataframes as df.1cleaned, df.2cleaned etc......
>
> Here are the steps to perform.
>
> 1.Create a new column named state, given by the last two letters of the
name field
> 2. Only keep rows where network is HSPA
> 3. Multiple the speed column by 1000
>
> So df.1cleaned would look like
> Name                Network.       Speed.     State
> Hartford_CT.     HSPA.           10000.      CT
>
> Can someone help me come up with a loop or a function that loops through
all dataframes and produces all three dataframes
>
> Thanks
> Vijay
>
>
> Sent from my iPad
> ______________________________________________
> R-help at r-project.org mailing list
> 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.