Displaying 20 results from an estimated 10000 matches similar to: "Renaming column names according to another dataframe"
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
2012 Sep 27
4
Colsplit, removing parts of a string
Hi,
I am using colsplit (package = reshape) to split all strings
in a column according to the same patterns. Here
an example:
library(reshape2)
df1 <- data.frame(x=c("str1_name2", "str3_name5"))
df2 <- data.frame(df1, colsplit(df1$x, pattern = "_", names=c("str","name")))
This is nearly what I want but I want to remove the words
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 Feb 08
2
Split dataframe into new dataframes
Hi,
I want to split a dataframe based on a grouping variable (in one column). The resulting new
dataframes should be stored in a new variable. I tried to split the dataframe using split() and
to store it using a FOR loop, but thats not working so far:
df <- data.frame(A=c("A1","A1","A2","A2"),B=seq(1:4))
Fsplit <- function(x,y){
ls <-
2013 Mar 07
1
Colour branches/labels of dendrogram according to a grouping variable
Hi,
is there a way to color the branches or text label of the branches of
dendrograms e.g. from hclust() according to a grouping variable. Here
I have something in mind like:
http://www.sigmaaldrich.com/content/dam/sigma-aldrich/life-science/biowire/biowire-fall-2010/proteome-figure-1.Par.0001.Image.gif
(ectodermal, endodermal, mesodermal).
/johannes
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) <-
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
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[??]...
2012 Jan 24
2
reshape dataframe to array (pivot table)
Hello,
I would like to reshape a dataframe into an array. This is kind a similar task as Excel performs with a Pivot table. To illustrate it:
LOC <- factor(c(1,2,2,3,1,1))
SPEC1 <- c(0,0,23,0,12,11)
SPEC2 <- c(1,2,0,0,0,4)
df <- data.frame(LOC,SPEC1,SPEC2) # original dataframe
a <-
2007 Jun 22
1
speed issues / pros & cons: dataframe vs. matrix
I've read that certain operations performed on a matrix (e.g. ribind, cbind) are often much faster compared to operations performed on a data frame.
Other then the "bind functions", what are the main operations that are significantly faster on a a matrix?
I know that data frames allow for columnnames and rownames, and that each column in a data frame can have different data types.
2012 Feb 17
5
How to change the order of columns in a data frame?
Dear all,
I have a data frame in which the columns need to be ordered. The first column X is at the right position, but the remaining columns X1-Xn should be ordered like this: X1, X2, X3 etc instead of like below.
> colnames(pos1)
[1] "X" "X1" "X10" "X11" "X12" "X13" "X14" "X15" "X16"
2013 Jun 26
1
Error when using median as aggregation function in dcast
Hi,
I am trying to calculated various summary statistics using the dcast
function
of reshape2. This works perfectly for getting the mean, sum, length, sd. But
when I want to calculate the median I get an error. I tried it with and
without removing
NAs:
my_median <- function(x) median(x, na.rm = FALSE)
median_df <- dcast(patch_stats_dfm,formula=species~input+barriers,my_median)
Error in
2013 Jun 26
1
Margins in dcast (reshape2)
Hi,
I'd like to get mean values for the margins of my casted data.frame.
For the casting I am using dcast() from reshape2. However, when I set
the margins parameter (margins=c("grand\_row")) I get following error
concerning
an unrecognized escape character '\_'. So what is the correct command
to get the outermost margins only in reshape2?
/johannes
[[alternative HTML
2011 Nov 16
1
Replacing values in matrix/dataframe according to changing criteria
Hi there,
I am doing some network analysis working with k-cliques and over time I
want to see what nodes are members of what cliques and how big these
cliques are. I have managed to produce a matrix which shows which k-cliques
each node is part of over the 100 time periods (slow though) but I cannot
seem to calculate the size of each k-clique which is actually just a count.
Basically I have a
2013 Oct 08
3
Latin Hypercube Sample and transformation to uniformly distributed integers or classes
Hi,
I'd like to use Latin Hypercube Sampling (LHC) in the the context of
uncertainty / sensitivity analysis of a complex model with approximately 10
input variables. With the LHC approach I'd like to generate parameter
combinations for my model input variables.
Therefore I came across an simple example here on the mailing list (
2012 Sep 28
1
Crosstable-like analysis (ks test) of dataframe
Hi,
I have a dataframe with multiple (appr. 20) columns containing
vectors of different values (different distributions).
Now I'd like to create a crosstable
where I compare the distribution of each vector (df-column) with
each other. For the comparison I want to use the ks.test().
The result should contain as row and column names the column names
of the input dataframe and the cells should
2013 Jan 11
2
Merging list of dataframes with reshape merge_all
Hi,
I'd like to merge mutliple dataframes from a list of dataframes by some common
columns. The approach for simply merging 2 dataframes is working with:
merge(df1,df2,by=c("col1","col2","col3"),all=TRUE)
For mutliple dataframes in a list I try to use the merge_all command
from the package reshape.
The documentation states that the command takes a list of
2010 May 07
3
Find the three best values in every row
Hello,
i have a dataframe with the GDP for different Country (in the columns) and
Years (in the rows).
Now i want for every year the best three values, if possible with name of
the countries (columnnames).
For the best it's no problem but for the other two values.
Thanks,
Alfred
2009 Nov 29
3
How to z-standardize for subgroups?
Hi folks,
I have a dataframe df.vars with the follwing structure:
var1 var2 var3 group
Group is a factor.
Now I want to standardize the vars 1-3 (actually - there are many
more) by class, so I define
z.mean.sd <- function(data){
return.values <- (data - mean(data)) / (sd(data))
return(return.values)
}
now I can call for each var
z.var1 <- by(df.vars$var1, group,
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