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Pancho Mulongeni

2013-Jan-11 11:17 UTC

[R] Using table to get frequencies of several factors at once

Hi, I have a dataframe with n columns, but I am only looking at five of them.
And lots of rows, over 700.
So I would like to find frequencies for each of the numeric columns (variables)
using the table function. However, is there a fast way to produce a frequency
table where the 5 rows represent the 5 numeric variables and the columns refer
to the values (levels) of the respective numeric variables, which in this case
are 0 and 1.
The only way I have figured it out is via a for loop:
m<-seq(218,222,1) #these are columns of the variables in the larger dataframe
tm<-m[1:5] #I need this for the for loop
l.tm<-length(tm)
B<-matrix(nrow=l.tm,ncol=2)  #the matrix to hold the freqs
for (p in 1:l.tm) {
var.num<-m[p]
B[p,]<-table(DATA[,var.num])
}
> B     [,1] [,2]
[1,]  697    9
[2,]  512  194
[3,]  604  102
[4,]  700    6
[5,]  706  706
So the rows represent my five variables (columns) that occupy columns 218
through 222 in the DATA dataframe.
So the second column represents my frequencies of the value 1, which is what I
am interested in. The last row has a double entry, because there was only one
value, 0, with a freq of 706 and so R duplicated in the two columns, but
that's ok, I can just ignore it.

So is there are better way to do this? Is there a way to use the so called
tapply function? I struggle to understand the help doc for this.function.


Pancho Mulongeni
Research Assistant
PharmAccess Foundation
1 Fouch? Street
Windhoek West
Windhoek
Namibia
?
Tel:?? +264 61 419 000
Fax:? +264 61 419 001/2
Mob: +264 81 4456 286

John Kane

2013-Jan-11 14:22 UTC

head link

[R] Using table to get frequencies of several factors at once

Does something like this do what you want?  It returns a list of tables

md  <-  data.frame((matrix(sample(1:5, 100, replace = TRUE),nrow= 10)))
  str(md)
  apply(md, 2, table)

John Kane
Kingston ON Canada

> -----Original Message-----
> From: p.mulongeni at namibia.pharmaccess.org
> Sent: Fri, 11 Jan 2013 11:17:42 +0000
> To: r-help at r-project.org
> Subject: [R] Using table to get frequencies of several factors at once
> 
> Hi, I have a dataframe with n columns, but I am only looking at five of
> them. And lots of rows, over 700.
> So I would like to find frequencies for each of the numeric columns
> (variables) using the table function. However, is there a fast way to
> produce a frequency table where the 5 rows represent the 5 numeric
> variables and the columns refer to the values (levels) of the respective
> numeric variables, which in this case are 0 and 1.
> The only way I have figured it out is via a for loop:
> m<-seq(218,222,1) #these are columns of the variables in the larger
> dataframe
> tm<-m[1:5] #I need this for the for loop
> l.tm<-length(tm)
> B<-matrix(nrow=l.tm,ncol=2)  #the matrix to hold the freqs
> for (p in 1:l.tm) {
> var.num<-m[p]
> B[p,]<-table(DATA[,var.num])
> }
> 
>> B
>      [,1] [,2]
> [1,]  697    9
> [2,]  512  194
> [3,]  604  102
> [4,]  700    6
> [5,]  706  706
> So the rows represent my five variables (columns) that occupy columns 218
> through 222 in the DATA dataframe.
> So the second column represents my frequencies of the value 1, which is
> what I am interested in. The last row has a double entry, because there
> was only one value, 0, with a freq of 706 and so R duplicated in the two
> columns, but that's ok, I can just ignore it.
> 
> So is there are better way to do this? Is there a way to use the so
> called tapply function? I struggle to understand the help doc for
> this.function.
> 
> 
> Pancho Mulongeni
> Research Assistant
> PharmAccess Foundation
> 1 Fouch? Street
> Windhoek West
> Windhoek
> Namibia
> 
> Tel:?? +264 61 419 000
> Fax:? +264 61 419 001/2
> Mob: +264 81 4456 286
> 
> ______________________________________________
> 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.
____________________________________________________________
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S Ellison

2013-Jan-16 14:27 UTC

head link

[R] Using table to get frequencies of several factors at once

You could use a variant of apply(), probably sapply

For example
d <- as.data.frame( matrix(sample(0:1, 200, replace=TRUE), ncol=5))

head(d)

sapply(d, table)

S Ellison> -----Original Message-----
> From: r-help-bounces at r-project.org 
> [mailto:r-help-bounces at r-project.org] On Behalf Of Pancho Mulongeni
> Sent: 11 January 2013 11:18
> To: R help
> Subject: [R] Using table to get frequencies of several factors at once
> 
> Hi, I have a dataframe with n columns, but I am only looking 
> at five of them. And lots of rows, over 700. 
> So I would like to find frequencies for each of the numeric 
> columns (variables) using the table function. However, is 
> there a fast way to produce a frequency table where the 5 
> rows represent the 5 numeric variables and the columns refer 
> to the values (levels) of the respective numeric variables, 
> which in this case are 0 and 1.  
> The only way I have figured it out is via a for loop:
> m<-seq(218,222,1) #these are columns of the variables in the 
> larger dataframe tm<-m[1:5] #I need this for the for loop
> l.tm<-length(tm)
> B<-matrix(nrow=l.tm,ncol=2)  #the matrix to hold the freqs 
> for (p in 1:l.tm) { var.num<-m[p]
> B[p,]<-table(DATA[,var.num])
> }
> 
> > B
>      [,1] [,2]
> [1,]  697    9
> [2,]  512  194
> [3,]  604  102
> [4,]  700    6
> [5,]  706  706
> So the rows represent my five variables (columns) that occupy 
> columns 218 through 222 in the DATA dataframe.
> So the second column represents my frequencies of the value 
> 1, which is what I am interested in. The last row has a 
> double entry, because there was only one value, 0, with a 
> freq of 706 and so R duplicated in the two columns, but 
> that's ok, I can just ignore it. 
> 
> So is there are better way to do this? Is there a way to use 
> the so called tapply function? I struggle to understand the 
> help doc for this.function.
> 
> 
> Pancho Mulongeni
> Research Assistant
> PharmAccess Foundation
> 1 Fouch? Street
> Windhoek West
> Windhoek
> Namibia
> ?
> Tel:?? +264 61 419 000
> Fax:? +264 61 419 001/2
> Mob: +264 81 4456 286
> 
> ______________________________________________
> 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.
> 
*******************************************************************
This email and any attachments are confidential. Any use...{{dropped:8}}

Greg Snow

2013-Jan-18 02:41 UTC

head link

[R] Using table to get frequencies of several factors at once

The tables package may be of use to you for this.


On Fri, Jan 11, 2013 at 4:17 AM, Pancho Mulongeni <
p.mulongeni@namibia.pharmaccess.org> wrote:
> Hi, I have a dataframe with n columns, but I am only looking at five of
> them. And lots of rows, over 700.
> So I would like to find frequencies for each of the numeric columns
> (variables) using the table function. However, is there a fast way to
> produce a frequency table where the 5 rows represent the 5 numeric
> variables and the columns refer to the values (levels) of the respective
> numeric variables, which in this case are 0 and 1.
> The only way I have figured it out is via a for loop:
> m<-seq(218,222,1) #these are columns of the variables in the larger
> dataframe
> tm<-m[1:5] #I need this for the for loop
> l.tm<-length(tm)
> B<-matrix(nrow=l.tm,ncol=2)  #the matrix to hold the freqs
> for (p in 1:l.tm) {
> var.num<-m[p]
> B[p,]<-table(DATA[,var.num])
> }
>
> > B
>      [,1] [,2]
> [1,]  697    9
> [2,]  512  194
> [3,]  604  102
> [4,]  700    6
> [5,]  706  706
> So the rows represent my five variables (columns) that occupy columns 218
> through 222 in the DATA dataframe.
> So the second column represents my frequencies of the value 1, which is
> what I am interested in. The last row has a double entry, because there was
> only one value, 0, with a freq of 706 and so R duplicated in the two
> columns, but that's ok, I can just ignore it.
>
> So is there are better way to do this? Is there a way to use the so called
> tapply function? I struggle to understand the help doc for this.function.
>
>
> Pancho Mulongeni
> Research Assistant
> PharmAccess Foundation
> 1 Fouché Street
> Windhoek West
> Windhoek
> Namibia
>
> Tel:   +264 61 419 000
> Fax:  +264 61 419 001/2
> Mob: +264 81 4456 286
>
> ______________________________________________
> 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.
>


-- 
Gregory (Greg) L. Snow Ph.D.
538280@gmail.com

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