Displaying 20 results from an estimated 20000 matches similar to: "Split dataframe into new dataframes"
2013 Mar 13
5
string split at xth position
Hi,
I have a vector of strings like:
c("a1b1","a2b2","a1b2") which I want to spilt into two parts like:
c("a1","a2","a2") and c("b1","b2,"b2"). So there is
always a first part with a+number and a second part with b+number.
Unfortunately there is no separator I could use to directly split
the vectors.. Any idea
2012 May 31
3
Remove columns from dataframe based on their statistics
Hi,
I have a dataframe and want to remove columns from it
that are populated with a similar value (for the total
column) (the variation of that column is 0). Is there an
easier way than to calculate the statistics and then
remove them by hand?
A <- runif(100)
B <- rep(1,100)
C <- rep(2.42,100)
D <- runif(100)
df <- data.frame(A,B,C,D) # if want to conditionally remove column B and
2012 Jun 08
4
Sort 1-column dataframe with rownames
Hi,
I have a 1-column dataframe with rownames and I want to sort it
based on the single column. The typical procedure that is recommended
in diverse posts is to use order in the index. But that "destroys" my
dataframe structure. Probabaly it is a very simple solution. Here is a
short reproducable example:
x <- c(1,3,51,2,34,44,12,33,2,8)
df <- data.frame(x)
rownames(df) <-
2011 Nov 24
2
dataframe indexing by number of cases per group
Hello,
assume we have following dataframe:
group <-c(rep("A",5),rep("B",6),rep("C",4))
x <- c(runif(5,1,5),runif(6,1,10),runif(4,2,15))
df <- data.frame(group,x)
Now I want to select all cases (rows) for those groups
which have more or equal 5 cases (so I want to select
all cases of group A and B).
How can I use the indexing for such questions?
df[??]...
2011 Dec 06
5
Argument validation within functions
Hi,
I just started with writing functions in R and so some questions popped up.
I provide some values as argument to my function such as:
function(a,b,c){}
Now i want that the function first checks if the arguments are valid for the function. E.g argument "a" has to be a number in the range 0-1. How can that easily done?
So far I have:
a <- as.numeric(a)
if(0 <= a &&
2012 Feb 03
2
Assigning objects to variable and variable to list in a for loop
Hello,
I want to use a for loop for repeadely calculating
a maxent model (package dismo, function maxent()) which
creates an object of the class maxent (S4).
I want to collect all the resulting object in a list.
I tried to simplify my for loop to explain what I want.
There are two problems/questions:
1) How can I create the new variables in the loop (using paste) and assign the objects
2) How
2011 Aug 15
2
Extracting information from lm results (multiple model runs)
Just to inform:
I posted that before in R-sig-ecology but as it might be interesting also for other useRs, I post it also to the general r-user list:
Hello Alexandre,
thank you very much. I also found another way to extract summarizing information from lm results over e.g. 1000 repeated model runs:
results2 <- t(as.data.frame(results))
summary(results2)
Although some questions popped up in
2013 Jan 11
3
split & rbind (cast) dataframe
Hi,
I would like to split dataframe based on one colum and want
to connect the two dataframes by rows (like rbind). Here a small example:
# The orgininal dataframe
df1 <- data.frame(col1 = c("A","A","B","B"),col2 = c(1:4), col3 = c(1:4))
# The datafame how it could look like
df2 <- data.frame(A.col2 = c(1,2), A.col3 = c(1,2), B.col2 = c(3,4),
B.col3
2011 Aug 15
2
MCMC regress, using runif()
Hello,
just to follow up a question from last week. Here what I've done so far (here an example):
library(MCMCpack)
Y=c(15,14,23,18,19,9,19,13)
X1=c(0.2,0.6,0.45,0.27,0.6,0.14,0.1,0.52)
X2a=c(17,22,21,18,19,25,8,19)
X2b=c(22,22,29,34,19,26,17,22)
X2 <- function()runif(length(X2a), X2a, X2b)
model1 <- MCMCregress(Y~X1+X2())
summary(model1)
but I am not sure if my X2-function is
2012 Feb 14
3
Wildcard for indexing?
Hi,
I'd like to know if it is possible to use wildcards * for indexing...
E.g. I have a vector of strings. Now I'd like to select all elements
which start with A_*? I'd also need to combine that with logical operators:
"Select all elements of a vector that start with A (A*) OR that start with B (B*)"
Probably that is quite easy. I looked into grep() which I think might
2019 Dec 06
2
[DWARF5][SplitDwarf] question on using fsplit-dwarf-inlining option
Hi DebugInfo folks,
I have a question on using fsplit-dwarf-inlining option:
"-fsplit-dwarf-inlining, -fno-split-dwarf-inlining
Provide minimal debug info in the object/executable to facilitate online
symbolication/stack traces in the absence of .dwo/.dwp files when using
Split DWARF"
i.e. it puts some debug info into compilation unit from First
partition(with Skeleton unit).
At
2012 May 11
2
text(): combine expression and line break
Hi,
I would like to plot some extra text in my plot.
This should be a two line text including a special character (sigma).
I tried so far a to use expression in combination with paste and "\n"...
but I can't get the line break...
Here what I've done so far:
plot(1,type="n", xaxt='n', yaxt='n', ann=FALSE)
text(1,1,labels=expression(paste(sigma,"\n
2011 Nov 03
2
variable transformation for lm
Hello,
I am doing a simple regression using lm(Y~X).
As my response and my predictor seemed to be skewed
and I can't meet the model assumptions. Therefore
I need to transform my variables.
I wanted to ask what is the preferred way to find out
if predictor and/or response needs to be transformed
and if yes how (log-transform?).
I found a procedure in "A modern approach to Regressoin
in
2012 Dec 11
5
Renaming column names according to another dataframe
Hi,
I've got a dataframe having a code as column name.
Addtionally I have another dataframe with a two columns (and lots of
rows), the first
containing the code and the second some Text (real name).
Now I'd like to use the information (pairs of code and name) of the
second dataframe to rename all the columnnames in the first dataframe.
How is it possible to achieve that?
Here a small
2011 Sep 07
1
linear regression, log-transformation and plotting
Hello,
I've some questions concerning log-transformations and plotting of the regression lines. So far as I know is it a problem to log-transform values smaller than 1 (0-1). In my statistics lecture I was told to do a log(x+1) transformation in such cases. So I provide here a small example to explain my questions:
# Some example data for testing
a1
2012 Jul 25
2
reshape -> reshape 2: function cast changed?
Hi,
I used to use reshape and moved to reshape2 (R 2.15.1). Now I tried some of my older scripts and was surprised that my cast function wasn't working like before.
What I did/want to do:
1) Melt a dataframe based on a vector specifying column names as measure.vars. Thats working so far:
dfm <- melt(df, measure.vars=n, variable_name = "species", na.rm = FALSE)
2) Recast the
2018 Feb 22
3
Loop splitting as a special case of unswitch
For the example code below,
int L = M + 10;
for (k = 1 ; k <=L; k++) {
dummy();
if (k < M)
dummy2();
}
, we can split the loop into two parts like :
for (k = 1 ; k != M; k++) {
dummy();
dummy2();
}
for (; k <=L; k++) {
dummy();
}
By splitting the loop, we can remove the conditional block in the loop and indirectly increase vectorization
2012 Jan 13
2
multidimensional array calculation
Hello,
probably it is quite easy but I can get it: I have
mulitple numeric vectors and a function using
all of them to calculate a new value:
L <- c(200,400,600)
AR <- c(1.5)
SO <- c(1,3,5)
T <- c(30,365)
fun <- function(L,AR,SO,T){
exp(L*AR+sqrt(SO)*log(T))
}
How can I get an array or dataframe where
all possible combinations of the factors are listed
and the new value is
2011 Aug 10
2
function runif in for loop
Hello,
I'd like to perform a regression using MCMCregress (MCMCpack).
One variable therefore should be a function rather than a variable:
I want to use X as an input and X should be defined as a random number between to values. Therefore I want to use the function runif like:
X <-(1, Xa, Xb) but it seems that runif doesn't allow to use vectors.
So I think I've to calculate the new
2011 Aug 15
2
plotting segments only and in color
Hello,
I've a question concerning the display of interval data.
A sample dataset where X is an interval between Xa and Xb
which should be displayed:
Y=c(15,14,23,18,19,9,19,13)
Xa=c(17,22,21,18,19,25,8,19)
Xb=c(22,22,29,34,19,26,17,22)
X = (Xa+Xb)/2
It's easily possible to plot the mean of the interval like:
plot(X,Y)
afterwards I can create lines for the interval with: