similar to: Another newbie question

Dear R-list, Seems simple but have tried multiple approaches, no luck. I have a list of column names:

LS, I would really like to know how to count the frequency/occurrence of chachters inside a dataset. I am working with extreemly large datasets of forest inventory data with a large variety of different species inside it. Each row inside the dataframe represents one individual tree and the simplified dataframe looks something like this: num species dbh 1 sp1

LS, I would really like to know how to count the frequency/occurrence of chachters inside a dataset. I am working with extreemly large datasets of forest inventory data with a large variety of different species inside it. Each row inside the dataframe represents one individual tree and the simplified dataframe looks something like this: num species dbh 1 sp1

Dear, I would like to post the following question to the r-help on Nabble (thanks in advance for the attention, Gustavo Vieira): Hi there. I have a data set on hands with 5,220 cases and I'd like to automate some procedures (but I have almost no programming knowledge). The data has some continuous variables that are grouped by 2 others: the name of species and the locality where they were

Dear all, how can I, with R, transform a presence-only table (with the names of the species (1st column), the lat information of the sites (2nd column) and the lon information of the sites (3rd column)) into a presence-absence (0/1) matrix of species occurrences across sites, as given in the below example? Thanks a lot for your help! Christian My initial table: species lat lon sp1 10 10

Dear list, I'm trying to create a matrix by combining the sites that species occur in a new matrix with species as rows and sites as columns. The main matrix is "mat": mat <- as.data.frame(cbind(sp1=c(rep(0, 5), rep(1, 5)),sp2=sample(c(rep(0, 6),rep(1, 4))), fac=c(rep("a", 3), rep("b", 3),rep("c", 4)))) The first two columns are species and the

Hello, I am trying to help a colleague with an R problem (see below) to whit I can only generate a very inelegant solution. Any advice would be welcome. Thanks, Brian If you have two matrices, say a species by trait matrix (Matrix 1 below) and a plot by species matrix (Matrix 2 below), is there a straightforward way to prune one matrix so that the species list matches those in a

Hi, I'm a very new user of R and I hope not to be too "basic" (I tried to find the answer to my questions by other ways but I was not able to). I have 12 response variables (species growth rates) and two environmental factors that I want to test to find out a possible relation. The sample size is quite small: (7<n<12, depending on each species-case). I performed a

Hello: I need to take a species-sample matrix and transpose it to the format used by PC-ORD for analysis. Unfortunately, the number of species is very large (>5000), and so this operation cannot be performed simply in an application like Excel, which has a 255 column limit. So, I wrote relatively simple code in R that I hoped would do this (appended below). But there are glitches. The

Hi, I have doubts in using subset command. I have a list of, lets say, 15 species and I want to make a subset with only 2 of them. I??m the command data2 <- subset(data1, species=="sp1"|species=="sp2") Nevertheless, when I ask for the summary (summary(data2)) the others species names still apearing. Also I tried data2<-data1(data1$species %in%

Hello, I am looking for a workaround of "species empty" plots in a correspondence analysis. I tried to do a community structure analysis with a ca via decorana(), ca() and CAIV(), but none of them allow 0 only-rows. I have species (abs./pres) in columns and sites in rows sp1 sp1 sp3 ... plot1 0 1 1 plot2 0 0 0 plot3 1 0 1 ..... but on some plots no

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Dear R-friends, I have to simple questions. First I would like to exclude some columns from a dataframe and after I need select rows that satisfy some conditions. My data frame looks like Region Species Bodysize Weigth Age Africa Sp1 10.2 20 2 Africa Sp2 12.2 12 2 Africa Sp3 15.3 18 3 Africa Sp4 11.5 40 4 Brazil Sp1 10.2 40 3 Brazil Sp2 22.2 32 2 Brazil Sp3 12.3

Dear R users, I have been having problems getting believable estimates from anova on a model fit from lmer. I get the impression that F is being greatly underestimated, as can be seen by running the example I have given below. First an explanation of what I'm trying to do. I am trying to fit a glmm with binomial errors to some data. The experiment involves 10 shadehouses, divided between

Dear R forum, I want to replace all the elements in a data frame (dd) which match the character "x" with "0". What's the most elegant way of doing this (there must be an easy way which I've missed)? I settled on the following loop: >for(i in 5:12){ # These are the column of dd I am interested in >dd[which(dd[,i]=="x"),i]<-0 >} The

Hi All, I am writing a simulation that examines the effects of species extinctions on ecological communties by sequentially removing individuals of a given species (sometimes using weighted probabilities) and replacing the lost individuals with species identities randomly sampled from the remaining individuals. Thus I use two dataframes. One contains all the individuals and their species

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I am trying to simulate a series of ones and zeros (1 or 0) and I am using "rbinom" but realizing that the number of successes expected is not accurate. Any advice out there. This is the example: N<-500 status<-rbinom(N, 1, prob = 0.15) count<-sum(status) 15 percent of 500 should be 75 but what I obtain from the "count" variable is 77 that gives the probability of

1. I have a list of lm (linear model) objects. Is it possible to select, through subscripts, a particular element (say, the intercept) from all the models? I've tried something like this: List[[1:length(list)]][1] All members of the list are similar. My goal is to have a list of the intercepts and lists of other estimated parameters. Is it better to convert to a matrix? How to do this? 2.

Hi, I have a small simple data frame (attached) - to compare diversity of insects encountered in disturbed and unditurbed site. What i have is the count of insects - the total number of times they were encountered over 30 monitoring slots. Can someone please check for me to make sure how the 'community data matrix' for the diversity function needs to be oriented so that i'm