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calculating time difference in R

You must turn your strings into date objects before you can do date/time arithmetic. Try this: a) Reading your data: R> dat <- read.table(textConnection(“start.date start.time end.date end.time 2012-07-13 15:01:32 2012-07-13 15:02:42 2012-07-05 18:26:31 2012-07-05 18:27:19 2012-07-14 20:23:21 2012-07-14 20:24:11”), header=TRUE) b) Working on one observation: R> strptime( paste(dat[,1], dat[,2]), “%Y-%m-%d %H:%M:%S”) [1] “2012-07-13 15:01:32” “2012-07-05 … Read more

R – Error : .onLoad failed in loadNamespace() for ‘rJava’

This worked for me – This error is often resolved by installing a Java version (i.e. 64-bit Java or 32-bit Java) that fits to the type of R version that you are using (i.e. 64-bit R or 32-bit R). This problem can easily effect Windows 7 users, since they might have installed a version of … Read more

Histogram with Logarithmic Scale and custom breaks

A histogram is a poor-man’s density estimate. Note that in your call to hist() using default arguments, you get frequencies not probabilities — add ,prob=TRUE to the call if you want probabilities. As for the log axis problem, don’t use ‘x’ if you do not want the x-axis transformed: plot(mydata_hist$count, log=”y”, type=”h”, lwd=10, lend=2) gets … Read more

ggplot2: Divide Legend into Two Columns, Each with Its Own Title

You can shift the “Very Good” category to the second column of the legend by adding a dummy factor level and setting its colour to white in the legend, so that it can’t be seen. In the code below, we add a blank factor level between “Good” and “Very Good”, so now we have six … Read more

Replace multiple strings in one gsub() or chartr() statement in R?

You can use gsubfn library(gsubfn) gsubfn(“.”, list(“‘” = “”, ” ” = “_”), x) # [1] “ab_c” Similarly, we can also use mgsub which allows multiple replacement with multiple pattern to search mgsub::mgsub(x, c(“‘”, ” “), c(“”, “_”)) #[1] “ab_c”

Format number in R with both comma thousands separator and specified decimals

format not formatC: format(round(as.numeric(1000.64), 1), nsmall=1, big.mark=”,”) # 1,000.6

ggplot plots in scripts do not display in Rstudio

The solution is to explicitly call print() on ggplot object: library(ggplot2) p <- ggplot(mtcars, aes(wt, mpg)) p <- p + geom_point() print(p) ggplot function returns object of class ggplot; ggplot2 works by overloading print function to behave differently on objects of class ggplot – instead of printing them to STDOUT, it creates chart. Everything is … Read more

Match values in data frame with values in another data frame and replace former with a corresponding pattern from the other data frame

You could try: merge(d,m, by.x=”v2″, by.y=”v3″) v2 v1 v4 1 A 1 a 2 A 7 a 3 B 4 b 4 B 5 b 5 C 3 c 6 C 6 c 7 E 2 e 8 E 8 e Edit Here is another approach, to preserve the order: data.frame(v1=d$v1, v4=m[match(d$v2, m$v3), 2]) v1 … Read more

Get filename without extension in R

There’s a built in file_path_sans_ext from the standard install tools package that grabs the file without the extension. tools::file_path_sans_ext(“ABCD.csv”) ## [1] “ABCD”