similar to: Creating data frame from existing data frame

Displaying 20 results from an estimated 50000 matches similar to: "Creating data frame from existing data frame"

2009 Sep 13
1
Manage an unknown and variable number of data frames
Hi, In the code below I create a small data.frame (dat) and then cut it into different groups using CutList. The lists in CutList allow to me choose whatever columns I want from dat and allow me to cut it into any number of groups by changing the lists. It seems to work OK but when I'm done I have a variable number of data frames what I need to do further operations on and I don't know
2009 Mar 19
2
Randomly splitting a data frame in half
I have a data frame in long format and I would like to randomly divide this data frame in half. The data frame consists of 39622 rows and I initially tried ... randomsample1 <- data[sample(nrow(data),19811), ] Where allows me to randomly select half of the rows and assign them to randomsample1 but then I couldn't figure out how to select those rows that were not selected and assign
2006 May 18
2
extracting values from data.frame given arbitrary keys
Hi all. I have a pure R programming question. Having a data.frame with a 'data' variable and some (>1) ID variables (either numeric or factors), I would extract a sequence of data values given a sequence of ID values. Here's an example. Build a dataset: n1 <- 5 n2 <- 2 v1 <- rep(factor(1:n1),2) v2 <- rep(1:n2,5) x <- rnorm(10) dat <- data.frame(x=x, v1=v1, v2=v2)
2006 Sep 06
1
Covariance/Correlation matrix for repeated measures data frame
All, I have a repeated measures data frame and was wondering if the covariance matrix can be calculated via some created indexing or built-in R function. Specifically, say there are 3 variables, where potassium concentration is measured 6 times on each patient. Patient number (discrete) Time (1 to 6, discrete) Potassium (continuous variable) I want the covariance/correlation matrix for the
2004 Dec 05
1
matrix of 1,0's to a data.frame of factors
Hi, I have an integer matrix consisting of 1's and 0's and I would like to convert this to a data.frame where each column of the matrix becomes a factor variable. Now, some columns of the matrix have only 1's or only 0's as a result there is only 1 level for those columns in the data.frame. However it is required that each factor have 2 levels. So my solution is: m <-
2009 Jul 24
2
How to find the min and max of two variables in a data frame
I have two variables in a data frame, I want to generate two additional variables. For every observations (i.e. every row), I want the first new variable 'min' to carry the minimum of the two existing variables, and I want the second new variable 'max' to carry the maximum of the two existing variables. I then want to sort the data frame by min and max, and delete duplicated rows
2010 May 11
2
Can not restore domain from a shared state file
Hi, I have two KVM host: h1 and h2, both of them mount an NFS directory as a shared storage. I can save (virsh save <domain> <file>) a domain in h1 to a state file in the shared storage successfully, but failed to restore it from h2 with the following error message: # virsh restore testRes.dat error: Failed to restore domain from testRes.dat error: operation failed: failed to start VM
2005 Feb 28
5
persistance of factor levels in a data frame
Hi, Just something I don't understand: data <- data.frame(V1=c(1:12),F1=c(rep("a",4),rep("b",4),rep("c",4))) data_ac <- data[which(data$F1 !="b"), ] levels(data_ac$F1) Why the level "b" is always present ? thanks Tristan, R 2.0.1 for Linux Fedora 3 -- ------------------------------------------------------------ Tristan
2004 Dec 01
2
Data Frame Manipulations
Hi I have used merge() to merge two data frames, very much like performing a SQL join. Now I want to do a few different SQL-style things and I wondered if there were functions to do it... Is there a "group by" style function? For example if I merge() two data frames and end up with multiple rows for each "id", and want to take the average of the values of a particular
2008 Mar 27
2
colMeans in a data.frame with numeric and character data
Hi all, I would like to know if it is posible by, someway, to get colMeans from a data.frame with numeric as well as character data, dispersed all over the object. Note that I would like to get colMeans neglecting character data. I am really in need of some function proceeding in that way… All the best Diogo André Alagador [[alternative HTML version deleted]]
2005 Mar 21
1
Remove columns from data-frame
Hello, I'm new to the list, hello everybody! :-) I have a question. I looked carefully through the documentation and googled, and found no answer, so I'm posting it here. Let's say I have a data frame with lots of columns (about 300), which are factors. Many columns-factors have only one level, for example all are "Yes" or all are "No". If I try to do a
2009 Feb 02
2
concatenating 2 text columns in a data.frame
Hi, I'm trying to concatenate values from two columns in a data frame. For example, I have the following data.frame: C1 C2 C3 C4 C5 A B *F C* Q G H *I J* T K D *R S* E P L *M N* O I'd like to concatenate text from columns C3 and C4, to yield either a list or vector, like so: NewCol FC IJ RS MN Is this feasible in R? Thanks!
2005 Mar 11
3
aov or t-test applied on all variables of a data.frame
Hi I have a data.frame with say 10 continuous variables and one grouping factor (say 3 levels) how can I easily (without loops) apply for each continous variable e.g. an aov, with the grouping factor as my factor (or if the grouping factor has 2 levels, eg. a t-test) thanks for a hint cheers christoph
2006 Nov 28
2
Sorting a data frame when you don't know the columns
Hi Sorry to ask such a well oiled question, but even with multiple google hits I don't think this has been answered very well. It's all well and good doing a sort of a data frame on multiple columns when you know in advance which columns you want to sort on, but what about when the names of the columns you wish to sort on are in a vector? At the minute I'm messing about with
2006 Jan 23
3
ordering a data frame to same order as a chr vector
Hi all, I've got a data frame that has an identical column to a chr vector. I would like to use the chr vector to order the rows of the data frame to be identical to the order in the chr vector (the contents of the chr vector are completely identical to one col of the data frame), but this is proving trickier than it sounds.. Any help would be much obliged, -Ken
2006 Jun 20
3
Create variables with common values for each group
Dear all, sorry, this is for sure really basic, but I searched a lot in the internet, and just couldn't find a solution. The problem is to create new variables from a data frame which contains both individual and group variables, such as mean age for an household. My data frame: df hhid h.age 1 10010020 23 2 10010020 23 3 10010126 42 4 10010126 60 5 10010142
2004 Oct 29
2
lag variable addition to data frame question
Hi, I was wondering if there is a more efficient way of handling the following method of creating a lagged value in a data frame without using the recursive 'for(i in 1:n)' loop and without using as.ts #Steps to creating a lag variable in a data frame 'my.dat.fr' # with 275 columns, 2400 rows of numbers and factors . The #variable x is a factor of #with five different levels the
2007 Apr 02
1
Res: Create a new var reflecting the order of subjects in existing var
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2006 Sep 12
1
Transformation of a data frame
Dear R-helpers, Apologies in advance for this (probably) simple question. I've searched the R Archive and can't seem to find a solution to my problem. I have a data frame of vegetation quadrat data with the following format: Q S C 1 A 5 1 B 10 1 C 50 1 D 10 2 A 20 2 E 10 2 C 40 3 D 5 3 F 1 3 G 5 3 B 75 Where Q is the sample (vegetation quadrats), S is the species and C is the
2007 Apr 03
1
Behavior of seq_along (was: Create a new var reflecting the order of subjects in existing var)
I am moving this from r-help to r-devel. Based on offline communications with Jim, suppose dat is defined as follows: set.seed(123) dat <- data.frame(ID= c(rep(1,2),rep(2,3), rep(3,3), rep(4,4), rep(5,5)), var1 =rnorm(17, 35,2), var2=runif(17,0,1)) # Then this ave call works as expected: ave(dat$ID, dat$ID, FUN = function(x) seq_along(x)) # but this apparently identical calculation