Martin

摘要： R语言数据储存与读取 1 首先用getwd() 获得当前目录，用setwd("C:/data")设定当前目录 2 数据保存 创建数据框d 2.1 保存为简单文本 2.2 保存为逗号分割文本 2.3 保存为R格式文件 2.4 保存工作空间镜像 3 数据读取 读取函数主要有：read.table( ), 阅读全文

摘要： test for data type is.numeric() is.character() is.vector() is.matrix() is.data.frame() convert it as.numeric() as.character() as.vector() as.matrix() 阅读全文

摘要： 举例 Examples Loops The most commonly used loop structures in R are for, while and apply loops. Less common are repeat loops. The break function is used 阅读全文

摘要： Arithmetic Operators Operator Description + addition - subtraction * multiplication / division ^ or ** exponentiation x %% y modulus (x mod y) 5%%2 is 1 x %/% y integer division 5%/... 阅读全文

摘要： f <- function(start_time) { start_time <- as.POSIXct(start_time) dt <- difftime(Sys.time(), start_time, units="secs") # Since you only want the H:M:S, we can ignore the date... # but you have... 阅读全文

摘要： # sorting examples using the mtcars dataset attach(mtcars) # sort by mpg newdata <- mtcars[order(mpg),] # sort by mpg and cyl newdata <- mtcars[order(mpg, cyl),] #sort by mpg (ascending) and cyl (... 阅读全文

摘要： Merging Data Adding Columns To merge two data frames (datasets) horizontally, use the merge function. In most cases, you join two data frames by one o 阅读全文

摘要： 1 Windows： 键入 cd C:\Program Files\R\R-3.2.0\bin 工作目录切换到R的核心程序目录键入 R BATCH F:\Test.R 或 Rscript F:\Test.R 运行脚本前者R控制台内容记录到Test.Rout文件中，后者则将数据输出到windows控制 阅读全文

摘要： Graphical Parameters You can customize many features of your graphs (fonts, colors, axes, titles) through graphic options. One way is to specify these 阅读全文

摘要： Sys.Date( ) #returns today's date. date() #returns the current date and time. # print today's date today <-Sys.Date() format(today, format="%B %d %Y") "June 20 2007" # convert date info in format '... 阅读全文