R For Loop Write CSV with List of Dataframes and Path Names

user_12522206 0
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I am trying to write a for loop in R with a list of dataframes and path names For some reason,the second dataframe is the only one that exports. Any help would be greatly appreciated.

df1 <- data.frame(num = sample(1:10, 6, replace = TRUE), letter = sample(LETTERS[1:2], 6, replace = 
TRUE))
df2 <- data.frame(num = sample(150:160, 6, replace = TRUE), letter = sample(LETTERS[1:2], 6, replace 
= TRUE))

list_dfs <- list(df1,df2)

paths <- c("C:\\Export\\file1.csv","C:\\Export\\file2.csv")

for (i in 1:length(list_dfs)) {
   for (f in 1:length(paths)) {
    write.csv(list_dfs[i], file = paths[f], row.names = FALSE)
  }
}
export-to-csv r for-loop
1 Answers

This should work:

for (i in 1:length(list_dfs)) {
  write.csv(list_dfs[i], file = paths[i], row.names = FALSE)
  }
}

The code you provided was writing list_dfs[1] to path[1] and then path[2]. Followed by list_dfs[2] to path[1] and then path[2], resulting in list_dfs[2] being written to path[1] and path[2].

If you want to include a check that list_dfs and paths are the same length you could do:

for (i in 1:length(list_dfs)) {
  if(length(list_dfs) != length(path)){stop("mismatch in number of data frames and paths")}
  write.csv(list_dfs[i], file = paths[i], row.names = FALSE)
  }
}

Ultimately though, if you want to export each data frame once, you only need one for() loop.

I hope this helps!

user_136391110
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