总结:按行合并,需要注意数据集需要有相同的列字段名
> #生成测试数据student1
> ID <- c(1:4)
> score <- c(8,22,7,33)
> student1<-data.frame...merge函数语法
merge(x, y, by = intersect(names(x), names(y)),
by.x = by, by.y = by, all = FALSE, all.x...= FALSE, suffix = c(".x", ".y"),
...)
left_join(x, y, by = NULL, copy = FALSE, suffix = c(".x", "....y"), ...)
right_join(x, y, by = NULL, copy = FALSE, suffix = c(".x", ".y"),
...)
full_join(x, y, by...student1,student2,by=c("ID","SD"))
ID SD name score
1 2 2 Tony 22
3 数据增减
常见如以下不同方法
#方法一:减行数或列数