R语言入门（19）-数据类型的转换_矩阵与数据框

矩阵转换成数据框

> library(xlsx)> setwd("C:/Users/Administrator/Desktop/R/RData")> cars32 <- read.xlsx("mtcars.xlsx",sheetIndex = 1,header = T)> is.data.frame(cars32)[1] TRUE> is.data.frame(state.x77)[1] FALSE> dstate.x77 <- as.data.frame(state.x77)> is.data.frame(dstate.x77)[1] TRUE

数据框转换成矩阵，如果数据框中既有数值也有字符串，转化成矩阵后，数值会变成字符串。

> head(as.matrix(data.frame(state.region,state.x77)))state.region Population Income Illiteracy Life.Exp Murder HS.Grad FrostAlabama "South"" 3615" "3624" "2.1""69.05" "15.1" "41.3" " 20"Alaska"West" " 365" "6315" "1.5""69.31" "11.3" "66.7" "152"Arizona "West" " 2212" "4530" "1.8""70.55" " 7.8" "58.1" " 15"Arkansas "South"" 2110" "3378" "1.9""70.66" "10.1" "39.9" " 65"California "West" "21198" "5114" "1.1""71.71" "10.3" "62.6" " 20"Colorado "West" " 2541" "4884" "0.7""72.06" " 6.8" "63.9" "166"Area Alabama " 50708"Alaska"566432"Arizona "113417"Arkansas " 51945"California "156361"Colorado "103766"

可以用method看as、is都有哪些函数可以进行数据转换

> methods(is)[1] is.Alignment is.arrayis.atomic [4] is.Borderis.call is.CellBlock [7] is.CellProtection is.CellStyle is.character [10] plex is.data.frame is.DataFormat[13] is.doubleis.element is.empty.model [16] is.environmentis.expression is.factor [19] is.Fill is.finiteis.Font[22] is.function is.infinite is.integer [25] is.language is.leaf is.list[28] is.loadedis.logical is.matrix [31] is.mts is.na is.na.data.frame [34] is.na.numeric_version is.na.POSIXlt is.na<-[37] is.na<-.default is.na<-.factoris.na<-.numeric_version[40] is.name is.nan is.null[43] is.numeric is.numeric.Date is.numeric.difftime [46] is.numeric.POSIXt is.numeric_versionis.object [49] is.ordered is.package_versionis.pairlist [52] is.primitive is.qr is.R [55] is.rasteris.raw is.recursive [58] is.relistable is.singleis.stepfun [61] is.symbolis.tableis.ts [64] is.tskernel is.unsorted is.vector see '?methods' for accessing help and source codeWarning message:In .S3methods(generic.function, class, envir) :function 'is' appears not to be S3 generic; found functions that look like S3 methods

unname（）

unlist（）