search for: kurt_helf

Greetings Though I have months in chronological order in my data table, the data were sampled every other month (i.e., February, April, June, August, October, December), every time I try to plot them (on the x-axis) they are plotted in alphabetical order. What am I missing? Cheers Kurt *************************************************************** Kurt Lewis Helf, Ph.D. Ecologist EEO

Greetings I want to remove numbers from a string of characters that identify sites so that I can merge two data frames. For example, a site in one frame is called "001a Frozen Niagara Entrance" whereas the same site in the other data frame is called "Frozen Niagara Entrance". It seems to me the easiest thing to do would be to remove the numbers from the first data

All Is there a script in R equivalent to the "if then" transforms one can perform in Systat? For example, I want to create a "Treatment" column coded either 1 or 2 for twelve field sites in a large data set. Ideally, I'd be able to tell R to code sites a-f as 1 and sites g-l as 2. Cheers Kurt *************************************************************** Kurt Lewis

Greetings Does anyone have any suggestions for reducing pdf file size, particularly pdfs containing photos, without sacrificing quality? Thanks for any tips in advance. Cheers Kurt *************************************************************** Kurt Lewis Helf, Ph.D. Ecologist EEO Counselor National Park Service Cumberland Piedmont Network P.O. Box 8 Mammoth Cave, KY 42259 Ph: 270-758-2163

Greetings Using the following command I've been trying to subset a dataframe of counts of an organism to compute the sizes of groups for use as a predictor: Hs.patches <- as.data.frame(with(Hs.long, table(Cave,Year,Month,Region,Plot,))) I am getting the following error message that I do not understand: ERROR: argument is missing, with no default Can anyone shed light on this

Greetings I have a bunch of NAs in a column of categorical variables designating the size classes (e.g., smallest to largest: 1,2,3,4) of cave crickets. I'd like to substitute "U" (for unknown) for the NAs. Can anyone give me an idea how to do this? Thanks in advance. Cheers Kurt *************************************************************** Kurt Lewis Helf, Ph.D. Ecologist

Greetings I'm having difficulty witht the strptime function. I can't seem to figure a way to strip month (name) and year and create separate columns from a column with MM/DD/YYYY formatted dates. Can anyone help? Cheers Kurt *************************************************************** Kurt Lewis Helf, Ph.D. Ecologist EEO Counselor National Park Service Cumberland Piedmont Network

Greetings How do I do this in R? Checking the Cran site produces a bewildering array of packages that I can't seem to find to load. Surely the main program has this function? Cheers Kurt *************************************************************** Kurt Lewis Helf, Ph.D. Invertebrate Ecologist National Park Service Cumberland Piedmont Network P.O. Box 8 Mammoth Cave, KY 42259 Ph:

Greetings I'm attempting to insert missing data on the smallest size class of cave cricket instars into a data frame. The data involve censusing photoplots (plots) of roosting cave crickets in which we discern in four instars or size classes. I need to insert data on size class one into a data frame that already has data on size classes two through four. The data can be merged by their

...robust standard errors for panel data (Millo Giovanni) 36. Re: Data Gaps (Dennis Murphy) 37. bwplot change whiskers position to percentile 5 and P95 (Christophe Bouffioux) 38. NA with lmList (FMH) 39. Re: NA with lmList (Phil Spector) 40. strip month and year from MM/DD/YYYY format (Kurt_Helf at nps.gov) 41. Re: Pipeline pilot fingerprint package (Rajarshi Guha) 42. Re: R: robust standard errors for panel data (max.e.brown at gmail.com) 43. Re: bwplot change whiskers position to percentile 5 and P95 (David Winsemius) 44. interaction contrasts (Kay Cichini) 45. Re:...

Greetings I need to merge two data sets. The first data set contains information on individual organisms roosting in clusters,e.g., cluster one has 5 individuals: 3 females, two males, and one juvenile and so on for hundreds of clusters. The second data set contains temperature data on each of the plots from the first data set. The problem: the second data set only has one data point per

Greetings I am attempting to plot observations of a cave aquatic invertebrate dating from 1901-2004. I can come up with a nice lattice plot of the eight sites from which I have data easily enough. However, I'd like to be able to highlight the 0 observations on the plots, i.e., attempts to find it at the site were unsuccessful. I'd like to be able to highlight these observations