我创建了 2 个数据框并尝试合并它。但它显示一个错误：“fix.by（by.x，x）中的错误：'by'必须指定一个唯一有效的列”[关闭]答案

【问题标题】：I created 2 data frame and I tried to merge it. But it shows an error: "Error in fix.by(by.x, x) : 'by' must specify a uniquely valid column" [closed]我创建了 2 个数据框并尝试合并它。但它显示一个错误：“fix.by（by.x，x）中的错误：'by'必须指定一个唯一有效的列”[关闭]
【发布时间】：2018-09-23 10:14:12
【问题描述】：

student<-data.frame("Roll_No"=c("202","203","204","205","206","157"),"First_Name"=c("Shahrukh","Shakti","Shantanu","Shashank","Shirke","Abhinav"),"Last_Name"=c("Khan","Rawat","Verma","Sinha","Ganesh","MIshra"),"State"=c("MP","MP","UT","UP","Maharashtra","MP"))

elec<-data.frame("Roll"=c("202","203","204","205","206","157"),"Subjects"=c("Operations","Operations","Operations","Analytics","Marketing","Marketing"))
print(student)
print(elec)

kpv <- merge(student,elec,by.x = c("ROll_No"),by.y = c("ROll"))

【问题讨论】：

标签： r dataframe merge

【解决方案1】：

注意变量名区分大小写的特性。在这里，我在您的合并调用中调整了它们：

student<-data.frame("Roll_No"=c("202","203","204","205","206","157"),"First_Name"=c("Shahrukh","Shakti","Shantanu","Shashank","Shirke","Abhinav"),"Last_Name"=c("Khan","Rawat","Verma","Sinha","Ganesh","MIshra"),"State"=c("MP","MP","UT","UP","Maharashtra","MP"))

elec<-data.frame("Roll"=c("202","203","204","205","206","157"),"Subjects"=c("Operations","Operations","Operations","Analytics","Marketing","Marketing")) 

print(student)
print(elec)

kpv <- merge(student,elec,by.x = c("Roll_No"),by.y = c("Roll"))
kpv

【讨论】：