Displaying 20 results from an estimated 10000 matches similar to: "extracting the last row of each group in a data frame"
2009 Dec 11
4
get the enclosing function name
Hi,
Is there a way to get the enclosing function name within a function?
For example, I would like to have a function getEnclosingFunctionName().
It works like below
f = function(){
print(getEnclosingFunctionName())
}
f() # will print "f"
Thanks
Jeff
2009 Dec 02
4
sort a data frame by a vector
Hi,
I have a a vector and a data frame with two columns
vec = c("C", "A", "B")
dataDF = data.frame(A1 = c("B", "A", "C"), A2 = c(1,2,3))
I would like to sort the data frame by column A1 such that the order of
elements in A1 is as the same as in vec.
After the ordering, the data frame would be
A1 A2
C
2008 Nov 17
5
how to calculate another vector based on the data from a combination of two factors
Hi,
I have a data set similar to the following
State Gender Quantity
TX Male 1
NY Female 2
TX Male 3
NY Female 4
I need to calculate cumulative sum of the quantity by State and Gender. The
expected output is
State Gender Quantity CumQuantity
TX Male 1 1
TX Male 3 4
NY Female 2 2
NY Female 4 6
I highly appreciate if someone can give me some hints on solving that in R.
Hao
--
View this
2009 Dec 29
2
pass functions and arguments to function
Hi,
I wonder how to pass several functions and their arguments as arguments to
a function. For example, the main function is
f = function(X ) {
process1(X)
...
process2(X)
}
I have a few functions that operate on X, e.g. g1(X, par1), g2(X, par2),
g3(X, par3). par1, par2 and par3 are parameters and of different types. I
would like to pass g1, g2, g3 and their arguments to f and g1,
2009 Dec 29
1
(no subject)
Hi,
I wonder how to pass several functions and their arguments as arguments to
a function. For example, the main function is
f = function(X ) {
process(X)
...
process(X)
}
I have a few functions that operate on X, e.g. g1(X, par1), g2(X, par2),
g3(X, par3). par1, par2 and par3 are parameters and of different types.
2009 Nov 24
1
ow to have R automatically print traceback upon errors
Hi,
I wonder how to have R automatically print stack trace produced by
traceback upon errors during interactive uses. I tried the suggestions on
http://old.nabble.com/Automatically-execute-traceback-when-execution-of-script-causes-error--td22368483.html#a22368775
and used options(error = recover)
options(showErrorCalls = T)
It just produces an extra message like "recover called
2009 Dec 29
1
how to append new data to saved data on disk efficiently
Hi,
I currently combine multiple processed data (data frame) into a list and
save the list as ".rda" using the save command. When new data come, I load
the rda file, process the new data into a data frame, append the data
frame to the end of the list, and save the whole list to the disk. The
loading and saving steps are quite time consuming. Since I don't need to
change the old data
2009 Nov 16
3
Sum over indexed value
I am sure this is easy but I am not finding a function to do this.
I have two columns in a matrix. The first column contains multiple entries
of numbers from 1 to 100 (i.e. 10 ones, 8 twos etc.). The second column
contains unique numbers. I want to sum the numbers in column two based on
the indexed values in column one (e.g. sum of all values in column two
associated with the value 1 in column
2010 Jan 08
2
how to organize a lot of R source files
Hi,
I wonder what is a better way to organize a lot of R source files. I have
a lot of utility functions written and store them in several source files
(e.g util1.R, util2.R,..utilN.R). I also have a master file in which the
source command is used to load all the util.R files. When I need to use
the utility functions in a new project, I create a new R file (e.g main.R)
in which I
2009 Nov 25
3
questions on the ff package
Hi,
I have two questions on using the ff package and wonder if anyone who used
ff can share some thoughts.
I need to save a matrix as a memory-mapped file and load it back later. To
save the matrix, I use
mat = matrix(1:20, 4, 5)
matFF = ff(mat, dim=dim(mat), filename="~/a.mat", overwrite=TRUE, dimnames
= dimnames(mat))
To load it back, I use
matFF2 = ff(vmode = "double",
2009 Dec 24
2
how to do multiple responses in a linear regression
Hi,
I have multiple responses y1, y2, .., yn, and would like to do linear
regression for each of them with x1, x2, ..., xm. Instead of doing
regression n times, it it possible to do it all at once?
I tried lm(y1+y2 ~ x1 + x2 + x3) and lm added y1 y2 and then did the
regression.
thanks
Jeff
2010 Feb 01
2
how to write a function that remembers its state across its calls
Hi,
I wonder how to write a function that remembers its state across its
calls. For example, I would like to compute the average of the pass three
values the function has seen
f(1) # NA
f(2) # NA
f(3) # 2
f(4) # 3
This would require f to keep track of the values it has seen. In other
languages like c++ or java it is easy to do by having a member variable. I
am not sure how to do similar
2009 Jun 12
1
Extracting the name of an object
With apologies if I missed the answer in the response given to my previous question.
How do I extract the name of an object and assign it to a string variable?
For example, I have a dataframe named comnoglyc
How do I assign this name to a variable dfname such that print(dfname) returns "comnoglyc"?
Thank you very much.
Payam
[[alternative HTML version deleted]]
2009 Nov 02
2
save an object by dynamicly created name
Hi,
I would like to save a few dynamically created objects to disk. The
following is the basic flow of the code segment
for(i = 1:10) {
m = i:5
save(m, file = ...) ## ???
}
To distinguish different objects to be saved, I would like to save m as m1,
m2, m3 ..., to file /home/data/m1, /home/data/m2, home/data/m3, ...
I tried a couple of methods on translating between object names and
2010 May 20
1
sqldf: issues with natural joins
Hello,
I'm having trouble discovering what's going wrong with my use of natural
joins via sqldf.
Following the instructions under 4i at http://code.google.com/p/sqldf/,
which discusses creating indices to speed joins, I have been only unreliably
able to get natural joins to work.
For example,
> Tid <- c('AES 01-01-02 10:58:00', 'AES 01-01-02 11:53:00', 'AES
2014 Jun 24
2
using C code to create data frame but always return as list
there is my code, expect return value is a data frame but R say it is list:
SEXP Julia_R_MD_NA_DataFrame(jl_value_t* Var)
{
SEXP ans,names,rownames;
char evalcmd[4096];
int i;
const char* dfname="DataFrameName0tmp";
jl_set_global(jl_main_module, jl_symbol(dfname), (jl_value_t*)Var);
//Get Frame cols
sprintf(evalcmd,"size(%s,2)",dfname);
jl_value_t*
2010 Jan 13
1
"select: bad file descriptor" in the multicore package
Hi,
I wonder anyone knows what causes the error message "select: bad file
descriptor" in the multicore package. This error sometimes occurs and
sometimes doesn't. I couldn't find any documentation on this error about
this package.
thanks
Jeff
2009 Jan 02
7
the first and last observation for each subject
I have the following data
ID x y time
1 10 20 0
1 10 30 1
1 10 40 2
2 12 23 0
2 12 25 1
2 12 28 2
2 12 38 3
3 5 10 0
3 5 15 2
.....
x is time invariant, ID is the subject id number, y is changing over time.
I want to find out the difference between the first and last observed y
value for each subject and get a table like
ID x y
1 10 20
2 12 15
3 5 5
......
Is there any easy way to generate
2009 Nov 20
1
how to link C code with gsl from R CMD and dyn.load
Hi,
I am writing a function in C that is meant to be called by R. In the C
function, I used a gsl function gsl_stats_mean. The code is as simple as
below
void gsl(double *m, int *dim){
int r, c;
r = dim[0];
c = dim[1];
double mean = gsl_stats_mean(&m[0], 1, r);
Rprintf("mean = %f\n", mean);
}
The C code is succesfully compiled and the output is as follows.
$ R CMD SHLIB
2009 Nov 12
1
how to pass matrices from C to R effectively
Hi,
I have C code to produce a lot of matrices to be analyzed. As these
matrices are large (> 1000*10000) and are a lot (> 1000), I am thinking
about how to pass them from C to R effectively.
Would you think about the following solution? In R, I create a wrapper
function
passDataFromCToR = function(row, col) {
mat = matrix(0, row, col)
.C("passDataFromCToR",mat)[[1]]
}