Merging data frames in R causes "names do not match previous names"

Question

I'm getting the "names do not match previous names" error when merging 2 data frames. However, they both have exactly the same names. I put ** surrounding the two places where I define the data frames but they are identical. What is going on? Thanks!

Exact error: Error in match.names(clabs, names(xi)) : names do not match previous names

corr <- function(directory, threshold = 0) {
    #store data frame that holds sulfate amount and nitrate amount that meet threshold and are complete cases
    **data <- data.frame(sulfate = numeric(0), nitrate = numeric(0))**

    #set working directory
    setwd(directory)

    #get file names
    myfiles <- list.files(pattern = "csv")

    #loop through files
    for(i in 1:332) {

        #read each file
        current_dataset <- read.csv(myfiles[i])

        #check if there are enough compelte cases to meet threshold
        if(sum(complete.cases(current_dataset)) > threshold) {

            #get complete cases
            complete_cases <- current_dataset[complete.cases(current_dataset), ]

            #add sulfate and nitrate info to table
            **data <- rbind(data, data.frame(sulfate = complete_cases$sulfate[i], nitrate = complete_cases$nitrate)[i])**
        }
    }
    #get correlation
    cor(data)
}

Are all of the parentheses in the correct place for the following line? data <- rbind(data, data.frame(sulfate = complete_cases$sulfate[i], nitrate = complete_cases$nitrate)[i]) — userNaN

Ben Bolker Ben Bolker · Accepted Answer · 2014-06-15T22:58:51

You haven't given a reproducible example, so I'm guessing, but I would try

...
for(i in seq_along(myfiles)) {
    #read each file
    current_dataset <- read.csv(myfiles[i])
    #check if there are enough complete cases to meet threshold
    if(sum(cc <- complete.cases(current_dataset)) > threshold) {
        #get complete cases
        complete_cases <- current_dataset[cc, ]
        #add sulfate and nitrate info to table
        data <- rbind(data, complete_cases[,c("sulfate","nitrate")])
    }
}

or

alldat <- lapply(myfiles,read.csv)
ccdat <- lapply(alldat,function(x) x[complete.cases(x),])
ccdat2 <- ccdat[sapply(ccdat,nrow)>threshold]
ccdat3 <- lapply(ccdat2,function(x) x[,c("sulfate","nitrate")])
final <- do.call(rbind,ccdat3)

Merging data frames in R causes "names do not match previous names"

1 Answers