similar to: expand.grid on contents of a list

Dear R-ers, I have a list of data frames such that the length of the list is unknown in advance (it could be 1 or 2 or more). Each element of the list contains a data frame. I need to loop through all rows of the list element 1 AND (if applicable) of the list element 2 etc. and do something at each iteration. I am trying to figure out how to write a code that is generic, i.e., loops through the

Hello! # I have a list with several data frames: mylist<-list(data.frame(a=1:2,b=2:3), data.frame(a=3:4,b=5:6),data.frame(a=7:8,b=9:10)) (mylist) # I want to grab only one specific column from each list element neededcolumns<-c(1,2,0) # number of the column I need from each element of the list # Below, I am doing it using a loop: newlist<-NULL for(i in 1:length(mylist) ) {

Hello! I have a large data frame x: x<-data.frame(item=letters[1:5],a=1:5,b=11:15) # in actuality, x has 1000 rows x$item<-as.character(x$item) I also have a small data frame y with just 1 row: y<-data.frame(item="f",a=3,b=10) y$item<-as.character(y$item) I have to decide if y$a is larger than the smallest of all the values in x$a. If it is, I want y to replace the whole

Hello! I have a data frame with several rows, for example: x=as.data.frame(matrix(c(1,2,3, 1,2,3, 1,2,2, 1,2,2, 1,1,1),ncol=3,byrow=T)) I would like to find y - a data frame that only has the unique rows from x, i.e.: 1,2,3 1,2,2 1,1,1 Thanks a lot for your hints! Dimitri -- Dimitri Liakhovitski gfk.com <http://marketfusionanalytics.com/> [[alternative HTML

Hello! # I have 3 vectors of values: values1<-rnorm(10) values2<-rnorm(10) values3<-rnorm(10) # In real life, all 3 vectors have a length of 25 # I create all possible combinations of 4 based on 10 elements: mycombos<-expand.grid(1:10,1:10,1:10,1:10) dim(mycombos) # Removing rows that contain pairs of identical values in any 2 of these columns: mycombos<-mycombos[!(mycombos$Var1

Dear R-ers, my task is to simple: to assign cases to desired groupings based on the combined values on 2 variables. I can think of 3 methods of doing it. Method 1 seems to me pretty r-like, but it requires a lot of lines of code - onerous. Method 2 is a loop, so not very good - as it loops through all rows of mydata. Method 3 is a loop but loops through fewer lines, so it seems to me more

Hello! I have a data set: set.seed(123) y<-data.frame(week=seq(as.Date("2010-01-03"), as.Date("2011-01-31"),by="week")) y$var1<-c(1,2,3,round(rnorm(54),1)) y$var2<-c(10,20,30,round(rnorm(54),1)) # All I need is to create lagged variables for var1 and var2. I looked around a bit and found several ways of doing it. They all seem quite complicated - while in

Hello! What function would allow me to "round" down, rather than up? For example, x<-1.98 I'd like to get 1.9 - rather than 2.0. Reason - I am creating a minimum for an axis for a plot, and I need it to be lower than x (which, in turn, is the lowest number already). Thank you! -- Dimitri Liakhovitski marketfusionanalytics.com

Hello! I have a data frame with some NAs. test<-data.frame(a=c(1,2,NA),b=c(10,NA,20)) I need to sum up values in 2 variables. However: test$a+test$b procudes NAs in rows that have NAs. How could I sum up columns while ignoring NAs (the way the function sum(..., na.rm=T) works? Thank you! -- Dimitri Liakhovitski marketfusionanalytics.com

Hello, dear R-ers! I built a data frame "grid" (below) with 4 columns. I want to exclude all rows that have equal values in ANY 2 columns. Here is how I am doing it: index<-expand.grid(1:4,1:4,1:4,1:4) dim(index) # Deleting rows that have identical values in any two columns (1 line of code):

Hello! I am trying to identify which ones of a vector of dates are US holidays. And, ideally, which is which. And I do not know (a-priori) which dates those should be. I have, for example: x<-seq(as.Date("2011-01-01"),as.Date("2011-12-31"),by="day") (x) I think chron should help me here - but maybe I am not using it properly: library(chron) is.holiday(chron) #

Hello! I have 2 maps - both created in ssplot and both identical in terms of outline. Is there any way to superimpose Map1 (which has black borders between Canadian provinces) onto Map2 (which is also a map of Canada)? Thanks a lot for your hints! Dimitri ### A. Reading in Canada data at the province and then at the county level: library(raster) getData('ISO3') # Canada's code is

Hello! I am trying to create an R optimization routine for a task that's currently being done using Excel (lots of tables, formulas, and Solver). However, otpim seems to be finding a local minimum. Example data, functions, and comparison with the solution found in Excel are below. I am not experienced in optimizations so thanks a lot for your advice! Dimitri ### 2 Inputs:

Hello, and apologies for not providing an example. However, my question is more general. I have a lengthy function. This function is using another internal function that modifies the data frame I am reading in. This internal function is using the command model.frame (with data and weights inside) and returns a data frame I am using for further analyses. However, when I try to run my function

Dear R-ers, I feel I am close, but can't get it quite right. Thanks a lot for your help! Dimitri # I have 2 data frames: x<-data.frame(a=c("aa","aa","ab","ab","ba","ba","bb","bb"),b=c(1:2,1:2,1:2,1:2),d=c(10,20,30,40,50,60,70,80))

Hello! It's a shoot in the dark, but I'll try. If one has a total of 100 (e.g., %), and three components of the total, e.g., mytotal=data.frame(x=50,y=30,z=20), - one could build a pie chart with 3 sectors representing x, y, and z according to their proportions in the total. I am wondering if it's possible to build something very similar, but not on a circle but in a square - such that

Hello! I am aggregating using a formula in aggregate - of the type: aggregate(cbind(var1,var2,var3)~factor1+factor2,sum,data=mydata) However, I actually have an object (vector of my variables to be aggregated): myvars<-c("var1","var2","var3") I'd like my aggregate formula (its "cbind" part) to be able to use my "myvars" object. Is it

Sorry if it's been discussed before - don't seem to find it. I'd like to calculate a mean while ignoring zeros. "mean" doesn't seem to have an option for that. Any other function/package that could do it? Thanks for a pointer! -- Dimitri Liakhovitski marketfusionanalytics.com

Hello! Hope you could help me split the strings. I have a set of strings: x<-c("name_a1_2.5.o","name_a2_2.53.o","name_a3_bla_1.o") I need to extract from each string: 1. Its unique part that comes before the last "_", i.e.: "a1","a2","a3_bla". 2. The part that comes after the last "_" and before ".o"

Hello! I have dates for the beginning of each week, e.g.: weekly<-data.frame(week=seq(as.Date("2010-04-01"), as.Date("2011-12-26"),by="week")) week # each week starts on a Monday I also have a vector of dates I am interested in, e.g.: july4<-as.Date(c("2010-07-04","2011-07-04")) I would like to flag the weeks in my weekly$week that