[R] Doing a Task Without Using a For Loop

2008-10-14 Thread Tom La Bone 

Assume that I have the dataframe "data1", which is listed at the end of this
message. I want count the number of lines that each person has for each
year. For example, the person with ID=213 has 15 entries (NinYear) for 1953.
The following bit of code calculates NinYear:

for (i in 1:length(data1$ID)) {
  data1$NinYear[i] <- length(data1[data1$Year==data1$Year[i] &
data1$ID==data1$ID[i],1]) }

This seems to work but is horribly slow (some files I am working with have
over 500,000 lines). Can anyone suggest a faster way of doing this, perhaps
a way that does not use a for loop? Thanks.

Tom

ID  YearNinYear
209 19710
209 19710
213 19510
213 19510
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19540
213 19540
213 19540
213 19540
213 19540
213 19540
213 19540
213 19540
213 19540
213 19540
213 19540
213 19550
213 19550
234 19530
234 19530
234 19530
234 19530
234 19530
234 19580
234 19580
234 19650
234 19650
234 19650
249 19520
249 19520



-- 
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http://www.nabble.com/Doing-a-Task-Without-Using-a-For-Loop-tp19974078p19974078.html
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Re: [R] Doing a Task Without Using a For Loop

2008-10-14 Thread Erik Iverson 

table(data1$ID, data1$Year)

See ?table and other functions referenced in ?table.



Tom La Bone wrote:

Assume that I have the dataframe "data1", which is listed at the end of this
message. I want count the number of lines that each person has for each
year. For example, the person with ID=213 has 15 entries (NinYear) for 1953.
The following bit of code calculates NinYear:

for (i in 1:length(data1$ID)) {
  data1$NinYear[i] <- length(data1[data1$Year==data1$Year[i] &
data1$ID==data1$ID[i],1]) }

This seems to work but is horribly slow (some files I am working with have
over 500,000 lines). Can anyone suggest a faster way of doing this, perhaps
a way that does not use a for loop? Thanks.

Tom

ID  YearNinYear
209 19710
209 19710
213 19510
213 19510
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19540
213 19540
213 19540
213 19540
213 19540
213 19540
213 19540
213 19540
213 19540
213 19540
213 19540
213 19550
213 19550
234 19530
234 19530
234 19530
234 19530
234 19530
234 19580
234 19580
234 19650
234 19650
234 19650
249 19520
249 19520





__
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Re: [R] Doing a Task Without Using a For Loop

2008-10-14 Thread Henrique Dallazuanna 
Try this:

with(data1, table(ID, Year))

On Tue, Oct 14, 2008 at 10:58 AM, Tom La Bone <[EMAIL PROTECTED]>wrote:

>
> Assume that I have the dataframe "data1", which is listed at the end of
> this
> message. I want count the number of lines that each person has for each
> year. For example, the person with ID=213 has 15 entries (NinYear) for
> 1953.
> The following bit of code calculates NinYear:
>
> for (i in 1:length(data1$ID)) {
>  data1$NinYear[i] <- length(data1[data1$Year==data1$Year[i] &
>data1$ID==data1$ID[i],1]) }
>
> This seems to work but is horribly slow (some files I am working with have
> over 500,000 lines). Can anyone suggest a faster way of doing this, perhaps
> a way that does not use a for loop? Thanks.
>
> Tom
>
> ID  YearNinYear
> 209 19710
> 209 19710
> 213 19510
> 213 19510
> 213 19530
> 213 19530
> 213 19530
> 213 19530
> 213 19530
> 213 19530
> 213 19530
> 213 19530
> 213 19530
> 213 19530
> 213 19530
> 213 19530
> 213 19530
> 213 19530
> 213 19530
> 213 19540
> 213 19540
> 213 19540
> 213 19540
> 213 19540
> 213 19540
> 213 19540
> 213 19540
> 213 19540
> 213 19540
> 213 19540
> 213 19550
> 213 19550
> 234 19530
> 234 19530
> 234 19530
> 234 19530
> 234 19530
> 234 19580
> 234 19580
> 234 19650
> 234 19650
> 234 19650
> 249 19520
> 249 19520
>
>
>
> --
> View this message in context:
> http://www.nabble.com/Doing-a-Task-Without-Using-a-For-Loop-tp19974078p19974078.html
> Sent from the R help mailing list archive at Nabble.com.
>
> __
> R-help@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.
>



-- 
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O

[[alternative HTML version deleted]]

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Re: [R] Doing a Task Without Using a For Loop

2008-10-14 Thread Claudia Beleites 
> This seems to work but is horribly slow (some files I am working with have
> over 500,000 lines). Can anyone suggest a faster way of doing this, perhaps
> a way that does not use a for loop? Thanks.
If the table solutions don't work or take forever with your real data, have a 
look into the wiki:
http://wiki.r-project.org/rwiki/doku.php?id=tips:data-frames:count_and_extract_unique_rows

Claudia

-- 
Claudia Beleites
Dipartimento dei Materiali e delle Risorse Naturali
Università degli Studi di Trieste
Via Alfonso Valerio 6/a
I-34127 Trieste

phone: +39 (0 40) 5 58-34 47
email: [EMAIL PROTECTED]

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Re: [R] Doing a Task Without Using a For Loop

2008-10-14 Thread Tom La Bone 

The table function, which I was unaware of, works great. However, I still
don't see how to assign the values calculated with table to data1$NinYear
without using a loop.

Tom 




Henrique Dallazuanna wrote:
> 
> Try this:
> 
> with(data1, table(ID, Year))
> 
> On Tue, Oct 14, 2008 at 10:58 AM, Tom La Bone
> <[EMAIL PROTECTED]>wrote:
> 
>>
>> Assume that I have the dataframe "data1", which is listed at the end of
>> this
>> message. I want count the number of lines that each person has for each
>> year. For example, the person with ID=213 has 15 entries (NinYear) for
>> 1953.
>> The following bit of code calculates NinYear:
>>
>> for (i in 1:length(data1$ID)) {
>>  data1$NinYear[i] <- length(data1[data1$Year==data1$Year[i] &
>>data1$ID==data1$ID[i],1]) }
>>
>> This seems to work but is horribly slow (some files I am working with
>> have
>> over 500,000 lines). Can anyone suggest a faster way of doing this,
>> perhaps
>> a way that does not use a for loop? Thanks.
>>
>> Tom
>>
>> ID  YearNinYear
>> 209 19710
>> 209 19710
>> 213 19510
>> 213 19510
>> 213 19530
>> 213 19530
>> 213 19530
>> 213 19530
>> 213 19530
>> 213 19530
>> 213 19530
>> 213 19530
>> 213 19530
>> 213 19530
>> 213 19530
>> 213 19530
>> 213 19530
>> 213 19530
>> 213 19530
>> 213 19540
>> 213 19540
>> 213 19540
>> 213 19540
>> 213 19540
>> 213 19540
>> 213 19540
>> 213 19540
>> 213 19540
>> 213 19540
>> 213 19540
>> 213 19550
>> 213 19550
>> 234 19530
>> 234 19530
>> 234 19530
>> 234 19530
>> 234 19530
>> 234 19580
>> 234 19580
>> 234 19650
>> 234 19650
>> 234 19650
>> 249 19520
>> 249 19520
>>
>>
>>
>> --
>> View this message in context:
>> http://www.nabble.com/Doing-a-Task-Without-Using-a-For-Loop-tp19974078p19974078.html
>> Sent from the R help mailing list archive at Nabble.com.
>>
>> __
>> R-help@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.
>>
> 
> 
> 
> -- 
> Henrique Dallazuanna
> Curitiba-Paraná-Brasil
> 25° 25' 40" S 49° 16' 22" O
> 
>   [[alternative HTML version deleted]]
> 
> 
> __
> R-help@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.
> 
> 

-- 
View this message in context: 
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Re: [R] Doing a Task Without Using a For Loop

2008-10-14 Thread Henrique Dallazuanna 
Is this what you want?

data1$NinYear <- with(data1, ave(ID, Year, FUN = length))

On Tue, Oct 14, 2008 at 12:22 PM, Tom La Bone <[EMAIL PROTECTED]>wrote:

>
> The table function, which I was unaware of, works great. However, I still
> don't see how to assign the values calculated with table to data1$NinYear
> without using a loop.
>
> Tom
>
>
>
>
> Henrique Dallazuanna wrote:
> >
> > Try this:
> >
> > with(data1, table(ID, Year))
> >
> > On Tue, Oct 14, 2008 at 10:58 AM, Tom La Bone
> > <[EMAIL PROTECTED]>wrote:
> >
> >>
> >> Assume that I have the dataframe "data1", which is listed at the end of
> >> this
> >> message. I want count the number of lines that each person has for each
> >> year. For example, the person with ID=213 has 15 entries (NinYear) for
> >> 1953.
> >> The following bit of code calculates NinYear:
> >>
> >> for (i in 1:length(data1$ID)) {
> >>  data1$NinYear[i] <- length(data1[data1$Year==data1$Year[i] &
> >>data1$ID==data1$ID[i],1]) }
> >>
> >> This seems to work but is horribly slow (some files I am working with
> >> have
> >> over 500,000 lines). Can anyone suggest a faster way of doing this,
> >> perhaps
> >> a way that does not use a for loop? Thanks.
> >>
> >> Tom
> >>
> >> ID  YearNinYear
> >> 209 19710
> >> 209 19710
> >> 213 19510
> >> 213 19510
> >> 213 19530
> >> 213 19530
> >> 213 19530
> >> 213 19530
> >> 213 19530
> >> 213 19530
> >> 213 19530
> >> 213 19530
> >> 213 19530
> >> 213 19530
> >> 213 19530
> >> 213 19530
> >> 213 19530
> >> 213 19530
> >> 213 19530
> >> 213 19540
> >> 213 19540
> >> 213 19540
> >> 213 19540
> >> 213 19540
> >> 213 19540
> >> 213 19540
> >> 213 19540
> >> 213 19540
> >> 213 19540
> >> 213 19540
> >> 213 19550
> >> 213 19550
> >> 234 19530
> >> 234 19530
> >> 234 19530
> >> 234 19530
> >> 234 19530
> >> 234 19580
> >> 234 19580
> >> 234 19650
> >> 234 19650
> >> 234 19650
> >> 249 19520
> >> 249 19520
> >>
> >>
> >>
> >> --
> >> View this message in context:
> >>
> http://www.nabble.com/Doing-a-Task-Without-Using-a-For-Loop-tp19974078p19974078.html
> >> Sent from the R help mailing list archive at Nabble.com.
> >>
> >> __
> >> R-help@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.
> >>
> >
> >
> >
> > --
> > Henrique Dallazuanna
> > Curitiba-Paraná-Brasil
> > 25° 25' 40" S 49° 16' 22" O
> >
> >   [[alternative HTML version deleted]]
> >
> >
> > __
> > R-help@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.
> >
> >
>
> --
> View this message in context:
> http://www.nabble.com/Doing-a-Task-Without-Using-a-For-Loop-tp19974078p19975745.html
> Sent from the R help mailing list archive at Nabble.com.
>
> __
> R-help@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.
>



-- 
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O

[[alternative HTML version deleted]]

__
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and provide commented, minimal, self-contained, reproducible code.

Re: [R] Doing a Task Without Using a For Loop

2008-10-14 Thread Dimitris Rizopoulos 

try the following:

out <- tapply(data1$ID, list(data1$ID, data1$Year), length)
out[is.na(out)] <- 0
out


I hope it helps.

Best,
Dimitris


Tom La Bone wrote:

Assume that I have the dataframe "data1", which is listed at the end of this
message. I want count the number of lines that each person has for each
year. For example, the person with ID=213 has 15 entries (NinYear) for 1953.
The following bit of code calculates NinYear:

for (i in 1:length(data1$ID)) {
  data1$NinYear[i] <- length(data1[data1$Year==data1$Year[i] &
data1$ID==data1$ID[i],1]) }

This seems to work but is horribly slow (some files I am working with have
over 500,000 lines). Can anyone suggest a faster way of doing this, perhaps
a way that does not use a for loop? Thanks.

Tom

ID  YearNinYear
209 19710
209 19710
213 19510
213 19510
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19540
213 19540
213 19540
213 19540
213 19540
213 19540
213 19540
213 19540
213 19540
213 19540
213 19540
213 19550
213 19550
234 19530
234 19530
234 19530
234 19530
234 19530
234 19580
234 19580
234 19650
234 19650
234 19650
249 19520
249 19520





--
Dimitris Rizopoulos
Assistant Professor
Department of Biostatistics
Erasmus Medical Center

Address: PO Box 2040, 3000 CA Rotterdam, the Netherlands
Tel: +31/(0)10/7043478
Fax: +31/(0)10/7043014

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Re: [R] Doing a Task Without Using a For Loop

2008-10-14 Thread Avram Aelony 



or perhaps...


data1$NinYear <- with(data1, ave(ID, Year, FUN = length))



> unique(data1)
ID Year NinYear
1  209 1971   2
3  213 1951   2
5  213 1953  20
20 213 1954  11
31 213 1955   2
33 234 1953  20
38 234 1958   2
40 234 1965   3
43 249 1952   2


Avram



On Oct 14, 2008, at 9:04 AM, Henrique Dallazuanna wrote:


Is this what you want?

data1$NinYear <- with(data1, ave(ID, Year, FUN = length))

On Tue, Oct 14, 2008 at 12:22 PM, Tom La Bone  
<[EMAIL PROTECTED]>wrote:




The table function, which I was unaware of, works great. However,  
I still
don't see how to assign the values calculated with table to data1 
$NinYear

without using a loop.

Tom




Henrique Dallazuanna wrote:


Try this:

with(data1, table(ID, Year))

On Tue, Oct 14, 2008 at 10:58 AM, Tom La Bone
<[EMAIL PROTECTED]>wrote:



Assume that I have the dataframe "data1", which is listed at the  
end of

this
message. I want count the number of lines that each person has  
for each
year. For example, the person with ID=213 has 15 entries  
(NinYear) for

1953.
The following bit of code calculates NinYear:

for (i in 1:length(data1$ID)) {
 data1$NinYear[i] <- length(data1[data1$Year==data1$Year[i] &
   data1$ID==data1$ID[i],1]) }

This seems to work but is horribly slow (some files I am working  
with

have
over 500,000 lines). Can anyone suggest a faster way of doing this,
perhaps
a way that does not use a for loop? Thanks.

Tom

ID  YearNinYear
209 19710
209 19710
213 19510
213 19510
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19530
213 19540
213 19540
213 19540
213 19540
213 19540
213 19540
213 19540
213 19540
213 19540
213 19540
213 19540
213 19550
213 19550
234 19530
234 19530
234 19530
234 19530
234 19530
234 19580
234 19580
234 19650
234 19650
234 19650
249 19520
249 19520



--
View this message in context:

http://www.nabble.com/Doing-a-Task-Without-Using-a-For-Loop- 
tp19974078p19974078.html

Sent from the R help mailing list archive at Nabble.com.

__
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PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.





--
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O

  [[alternative HTML version deleted]]


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View this message in context:
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tp19974078p19975745.html

Sent from the R help mailing list archive at Nabble.com.

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--
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O

[[alternative HTML version deleted]]

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guide.html

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Re: [R] Doing a Task Without Using a For Loop

2008-10-15 Thread jim holtman 
Run Rprof on your script that is updating the dataframe.  A dataframe
is a list and everytime you access something in the list it can be
expensive.  Rprof will probably show that a lot of time is spent in
the function "[[" which is accessing portions of the dataframe.
Vectors are much faster because they are typically sequentially in
memory and can be accessed easily.  Rprof is always helpful in
answering the question of "why is something taking so long".  It helps
you to find where the potential bottlenecks are.

On Wed, Oct 15, 2008 at 7:33 AM, Tom La Bone <[EMAIL PROTECTED]> wrote:
>
> I want to thank everyone for the help. I ended up having to use a loop to
> assign values from the table to NinYear. However, as I have played with the
> full datasets I have noticed that R is MUCH faster if I use vectors in the
> loop rather than columns of a dataframe. In the specific case of 43,000
> lines of data, assigning values from the table to the 43,000 elements of a
> vector took 6 seconds whereas assigning values from the table to 43,000
> elements of a dataframe took 21 minutes. Why is there such a huge
> difference?
>
> Tom
>
>
>
>
> Tom La Bone wrote:
>>
>> Assume that I have the dataframe "data1", which is listed at the end of
>> this message. I want count the number of lines that each person has for
>> each year. For example, the person with ID=213 has 15 entries (NinYear)
>> for 1953. The following bit of code calculates NinYear:
>>
>> for (i in 1:length(data1$ID)) {
>>   data1$NinYear[i] <- length(data1[data1$Year==data1$Year[i] &
>> data1$ID==data1$ID[i],1]) }
>>
>> This seems to work but is horribly slow (some files I am working with have
>> over 500,000 lines). Can anyone suggest a faster way of doing this,
>> perhaps a way that does not use a for loop? Thanks.
>>
>> Tom
>>
>> IDYearNinYear
>> 209   19710
>> 209   19710
>> 213   19510
>> 213   19510
>> 213   19530
>> 213   19530
>> 213   19530
>> 213   19530
>> 213   19530
>> 213   19530
>> 213   19530
>> 213   19530
>> 213   19530
>> 213   19530
>> 213   19530
>> 213   19530
>> 213   19530
>> 213   19530
>> 213   19530
>> 213   19540
>> 213   19540
>> 213   19540
>> 213   19540
>> 213   19540
>> 213   19540
>> 213   19540
>> 213   19540
>> 213   19540
>> 213   19540
>> 213   19540
>> 213   19550
>> 213   19550
>> 234   19530
>> 234   19530
>> 234   19530
>> 234   19530
>> 234   19530
>> 234   19580
>> 234   19580
>> 234   19650
>> 234   19650
>> 234   19650
>> 249   19520
>> 249   19520
>>
>>
>>
>>
>
> --
> View this message in context: 
> http://www.nabble.com/Doing-a-Task-Without-Using-a-For-Loop-tp19974078p19991682.html
> Sent from the R help mailing list archive at Nabble.com.
>
> __
> R-help@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.
>



-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem that you are trying to solve?

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Re: [R] Doing a Task Without Using a For Loop

2008-10-15 Thread Tom La Bone 

I want to thank everyone for the help. I ended up having to use a loop to
assign values from the table to NinYear. However, as I have played with the
full datasets I have noticed that R is MUCH faster if I use vectors in the
loop rather than columns of a dataframe. In the specific case of 43,000
lines of data, assigning values from the table to the 43,000 elements of a
vector took 6 seconds whereas assigning values from the table to 43,000
elements of a dataframe took 21 minutes. Why is there such a huge
difference?

Tom




Tom La Bone wrote:
> 
> Assume that I have the dataframe "data1", which is listed at the end of
> this message. I want count the number of lines that each person has for
> each year. For example, the person with ID=213 has 15 entries (NinYear)
> for 1953. The following bit of code calculates NinYear:
> 
> for (i in 1:length(data1$ID)) {
>   data1$NinYear[i] <- length(data1[data1$Year==data1$Year[i] &
> data1$ID==data1$ID[i],1]) }
> 
> This seems to work but is horribly slow (some files I am working with have
> over 500,000 lines). Can anyone suggest a faster way of doing this,
> perhaps a way that does not use a for loop? Thanks.
> 
> Tom
> 
> IDYearNinYear
> 209   19710
> 209   19710
> 213   19510
> 213   19510
> 213   19530
> 213   19530
> 213   19530
> 213   19530
> 213   19530
> 213   19530
> 213   19530
> 213   19530
> 213   19530
> 213   19530
> 213   19530
> 213   19530
> 213   19530
> 213   19530
> 213   19530
> 213   19540
> 213   19540
> 213   19540
> 213   19540
> 213   19540
> 213   19540
> 213   19540
> 213   19540
> 213   19540
> 213   19540
> 213   19540
> 213   19550
> 213   19550
> 234   19530
> 234   19530
> 234   19530
> 234   19530
> 234   19530
> 234   19580
> 234   19580
> 234   19650
> 234   19650
> 234   19650
> 249   19520
> 249   19520
> 
> 
> 
> 

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