Error in file(file, "rt") : cannot open the connection [duplicate]

I'm new to R, and after researching this error extensively, I'm still not able to find a solution for it. Here's the code. I've checked my working directory, and made sure the files are in the right directory. Appreciate it. Thanks

pollutantmean <- function(directory, pollutant = "nitrate", id= 1:332)            
{                 if(grep("specdata",directory) ==1) 
            {
                    directory <- ("./specdata")
            }
            mean_polldata <- c()
            specdatafiles <- as.character(list.files(directory))
            specdatapaths <- paste(directory, specdatafiles, sep="")
                            for(i in id) 
                    {
                    curr_file <- read.csv(specdatapaths[i], header=T, sep=",")
                    head(curr_file)
                    pollutant
                    remove_na <- curr_file[!is.na(curr_file[, pollutant]), pollutant]
                    mean_polldata <- c(mean_polldata, remove_na)
                    }
            {
                    mean_results <- mean(mean_polldata)
                    return(round(mean_results, 3))
            }
} 

The error I'm getting is below:

Error in file(file, "rt") : cannot open the connection

file(file, "rt")

read.table(file = file, header = header, sep = sep, quote = quote, 
    dec = dec, fill = fill, comment.char = comment.char, ...)

read.csv(specdatapaths[i], header = T, sep = ",")

pollutantmean3("specdata", "sulfate", 1:10)

In addition: Warning message:
In file(file, "rt") :
  cannot open file './specdata001.csv': No such file or directory

You need to change directory <- ("./specdata") to directory <- ("./specdata/")

Relative to your current working directory, you are looking for the file 001.csv, which is in your specdata directory.

This question is nearly impossible to answer without any context, since you have not provided us with the structure of your working directory here. Fortunately for you, I have already taken R Programming on Coursera, so I already did this homework question.

The reason why you see this error I guess is because RStudio lost the path of your working directory.

(1) Go to session...

(2) Set working directory...

(3) Choose directory...

--> Then you can see a window pops up.

--> Choose the folder where you store your data.

This is the way without any code that you change your working directory. Hope this can help you.

Set your working directory one level/folder higher. For example, if it is already set as:

setwd("C:/Users/Z/Desktop/Files/RStudio/Coursera/specdata")

go up one level back and set it as:

setwd("C:/Users/Z/Desktop/Files/RStudio/Coursera")

In other words, do not make "specdata" folder as your working directory.

I just spent a lot of time trying to understand what was wrong on my code too...

And it seems to be simple if you are using windows.

When you name your file "blabla.txt" then windows name it "blabla.txt.txt"... That's the same with .CSV files so windows create a file named "001.csv.csv" if you called it "001.csv"

So, when you create your .csv file, just rename it "001" and open it in R using read.table("/absolute/path/of/directory/with/required/001.csv")

It works for me.

close your R studio and run it again as an administrator. That did the magic for me. Hope it works for you and anyone going through this too.