Reading data from csv files is very useful as csv file is a standard output of many programs. In R, you can read csv file in one line: df <- read.csv("/path/to/file.txt", row.names=1,head=FALSE, sep=",")df <- read.csv("/path/to/file.txt", row.names=1,head=FALSE, sep=",") The code above specifies the first column is just a name by using row.names=1. By using head=FALSE, it … Read more
Vector, Array, List and Data Frame are 4 basic data types defined in R. Knowing the differences between them will help you use R more efficiently. 1. Vector All elements must be of the same type. For example, the following code create two vectors. name y y $name [1] “Mike” $gender [1] “M” $company [1] … Read more
How to set page title font size is not clear in R’s documentation. It can take a lot of time to figure out how to set font size. The following code shows how to change font size. # create a simple data frame a
The page size can be set by using the following line: pdf(“plot.pdf”, width=8,height=11) The code above set the page size to 8 multiply 11, which is the letter size. The following is a complete example. # create a simple data frame a
You may want to add a title for a plot page that contains multiple diagrams. The following R code plot 3 diagrams on one page, and add a title to the page. # create a simple data frame a
You can plot multiple diagrams on one page by using par() to set up the page layout. The following R code plot multiple diagrams on one page. # create a simple data frame a
If you want to declare an empty vector in R, you can do the following: vec
In R, we can easily write a date frame object to a csv file. By using the method write.csv, the csv file can be generated under the same directory of your R script. write.csv(dataFrame, file=”median.csv”)
Installing R on Mac is very easy. Just download the installation file here: http://cran.r-project.org/bin/macosx/. The bin files will be automatically added to the PATH.
Installing R on Windows is pretty straightforward. Just go to the page and download the installation file here. Remember you need to add the bin directory to your “Path” environment variable.
Sometimes, you may want to run R Script by using command line. In this way, you can write a bash script and schedule a task everyday. In addition you can also pass different arguments to the R program. Create a R script “GetARgument.R”: args
The R code below reads a file line by line. path <- "/path/to/the/file" print(path) conn <- file(path,open="r") lines <- readLines(conn) for (i in 1:length(lines)){ print(lines[i]) } close(conn)path <- "/path/to/the/file" print(path) conn <- file(path,open="r") lines <- readLines(conn) for (i in 1:length(lines)){ print(lines[i]) } close(conn)