Error in data frame undefined columns selected

Question

I've been working on an assignment where I have to read in some csv files from a directory "specdata". The files are very similar in that there are 332 titled 001.csv - 332.csv. They have consistent columns and headers, if that matters. I believe I'm close but am tripping up with the above error message " Error in `[.data.frame`(data1, good) : undefined columns selected" I had expected a data frame to load with all the data specified by the subset of files in id parameter. ``` pollutantmean <- function(directory, pollutant, id = 1:332) { files <- list.files(directory) subsetFiles <- files[id] for (i in subsetFiles) { filepaths <- paste(directory,"/",i, sep='') data1 <- read.csv(filepaths) } data1 good <- complete.cases(data1) data2 <- data1[good] data2 } # test it out and ignore middle parameter for now pollutantmean("specdata", "pass", 1:3) ```

Accepted Answer

Are you meaning?

```
data2 <- data1[good,]
```

With

```
data1[good]
```

you're selecting columns in a wrong way (using a logical vector of complete rows).

Consider that parameter `pollutant` is not used; is it a column name that you want to extract? if so it should be something like

```
data2 <- data1[good, pollutant]
```

Furthermore consider that you have to `rbind` the `data.frame`s inside the `for` loop, otherwise you get only the last data.frame (its completed.cases)

And last but not least, i'd prefer generating filenames eg with

```
id <- 1:322
paste0( directory, "/", gsub(" ", "0", sprintf("%3d",id)), ".csv")
```

A little modified chunk of `?sprintf`

The string `fmt` (in our case `"%3d"`) contains normal characters, which are passed through to the output string, and also conversion specifications which operate on the arguments provided through `...`. The allowed conversion specifications start with a `%` and end with one of the letters in the set `aAdifeEgGosxX%`. These letters denote the following types:

- `d`: integer

Eg a more general example

```
    sprintf("I am %10d years old", 25)
[1] "I am         25 years old"
          ^^^^^^^^^^
          |        |
          1       10
```

Error in data frame undefined columns selected

Solution

Problem