R语言基础4(文件读写）

test =read.csv(file="")
##直接读取失败就需要加一些参数
write.csv(test,file="example.csv")
test =read.table(file="XXX.txt")
write.table(test,file="example.txt")
##导出时不要覆盖源文件

save(test,file="example.Rdata")
load("example.Rdata")

#1.读取ex1.txt
ex1 <- read.table("ex1.txt")
ex1 <- read.table("ex1.txt",header = T)##第一行为变量，作为列名；

#2.读取ex2.csv
ex2 <- read.csv("ex2.csv")
ex2 <- read.csv("ex2.csv",row.names = 1,check.names = F)
## check.names检查列名是否有特殊字符；
##row.names第一列作为行名；

#注意：数据框不允许重复的行名
rod = read.csv("rod.csv",row.names = 1)
rod = read.csv("rod.csv")
##先不加row.names = 1，读取去除重复值后再设置行名；

#3.读取soft.txt
soft <- read.table("soft.txt")
soft <- read.table("soft.txt",header = T,fill = T) #其实不对
soft2 <- read.table("soft.txt",header = T,sep = "\t")
sep=""##让一切看不见的符号都当做分隔符（制表符或空格）；只要看不见都看做一个分隔符；

#4.soft 的行数列数是多少？列名是什么
dim(soft)
colnames(soft)
#5.将soft导出为csv
write.csv(soft,file = "soft.csv")
#6.将soft保存为Rdata并加载。
save(soft,file = "soft.Rdata")
rm(list = ls())
load(file = "soft.Rdata")

#data.table
install.packages("data.table")
library(data.table)
soft = data.table::fread("soft.txt")
class(soft)
soft = data.table::fread("soft.txt",data.table = F)
class(soft)
#rio
install.packages("rio")
library(rio)
#读取
soft = import("soft.txt")
#读取多工作簿的excel
ls2 = rio::import_list("ls.xlsx")
#导出为普通表格文件
export(iris,file = "iris.csv")
#导出列表
ls = split(iris,iris$Species)
export(ls,file = "ls.xlsx")