读入外部文件

Delimited files（符号分割文件）

*based on the read.table()function

read.table(file, header, sep = , quote = , dec = , row.names, col.names,as.is = , na.strings , colClasses , nrows =, skip = ,check.names = , fill = , strip.white = , blank.lines.skip = ,comment.char = , allowEscapes = , flush = , stringsAsFactors = ,encoding = )

sep 假定每个字段之间都有一个分隔符：例如有一个文件top.5.salsries.csv，内容如下：

name.last,name.first,team,position,salary

“Manning”,”Peyton”,”Colts”,”QB”,18700000

“Brady”,”Tom”,”Patriots”,”QB”,14626720

“Pepper”,”Julius”,”Panthers”,”DE”,14137500

“Palmer”,”Carson”,”Bengals”,”QB”,13980000

“Manning”,”Eli”,”Giants”,”QB”,12916666

上例中，文本字段都是有引号的，每个字段由逗号分割。假定该文件在当前目录下，读取该文件：

top.5.salaries <- read.table("top.5.salaries.csv", header=TRUE, sep=",", quote="\"")