R语言-merge和rbind

rbind

使用方式 
合并两个数据集，要求两个数据集的列数相等：

rbind(parameter1,parameter2)

合并多个数据集，各个数据集的列数相等：

rbind(parameter1,parameter2,...,parametern)

从数据集中提取数据

test <- rbind() for (i in 1:length(s_5)) { test <- rbind(test,data[s_5[i],]) }

merge

merge函数的声明:

merge(x, y, by = intersect(names(x), names(y)), by.x = by, by.y = by, all = FALSE, all.x = all, all.y = all, sort = TRUE, suffixes = c(".x",".y"), incomparables = NULL, ...)

merge函数参数的说明:

参数	说明
x,y	用于合并的两个数据框
by,by.x,by.y	指定依据哪些行合并数据框,默认值为相同列名的列.
all,all.x,all.y	指定x和y的行是否应该全在输出文件.
sort	by指定的列是否要排序.
suffixes	指定除by外相同列名的后缀.
incomparables	指定by中哪些单元不进行合并.

例子:

w1: NAME SCHOOL CLASS ENGLISH A S1 10 85 B S2 5 50 A S1 4 90 A S1 11 90 C S1 1 12 w2: NAME SCHOOL CLASS MATHS ENGLISH A S3 5 80 88 B S2 5 89 81 C S1 1 55 32

按照NAME, SCHOOL, CLASS合并w1和w2:

merge(w1, w2, all = T) NAME SCHOOL CLASS ENGLISH MATHS 1 A S1 4 90 NA 2 A S1 10 85 NA 3 A S1 11 90 NA 4 A S3 5 88 80 5 B S2 5 50 NA 6 B S2 5 81 89 7 C S1 1 12 NA 8 C S1 1 32 55 merge(w1, w2, by = c("NAME", "SCHOOL", "CLASS"), all = T) NAME SCHOOL CLASS ENGLISH.x MATHS ENGLISH.y A S1 4 90 NA NA A S1 10 85 NA NA A S1 11 90 NA NA A S3 5 NA 80 88 B S2 5 50 89 81 C S1 1 12 55 32 merge(w1, w2, all = T, incomparables = "A") Error in merge.data.frame(w1, w2, all = T, incomparables = "A") : 'incomparables' is supported only for merging on a single column merge(w1, w2, all = T, by = "NAME", incomparables = "A") NAME SCHOOL.x CLASS.x ENGLISH.x SCHOOL.y CLASS.y MATHS ENGLISH.y A S1 10 85 <NA> NA NA NA A S1 4 90 <NA> NA NA NA A S1 11 90 <NA> NA NA NA A <NA> NA NA S3 5 80 88 B S2 5 50 S2 5 89 81 C S1 1 12 S1 1 55 32

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横向合并

ID<-c(1,2,3,4) name<-c("Jim","Tony","Lisa","Tom") score<-c(89,22,78,78) student1<-data.frame(ID,name) student2<-data.frame(ID,score) total_student<-merge(student1,student2,by="ID") total_student

当然merge也可以使用纵向合并

merge(data1,dadta2,all=T)

纵向合并

ID<-c(1,2,3) name<-c("Jame","Kevin","Sunny") student1<-data.frame(ID,name) ID<-c(4,5,6) name<-c("Sun","Frame","Eric") student2<-data.frame(ID,name) total<-rbind(student1,student2) total