Remove rows with missing values in R

Question

I want to remove all rows with NAs, I tried na.omit, but I still have all the "#N/A" values in my data...

This is my code:

mydata = read.csv('file:///C:/Users/file.csv')
mydata = as.data.frame(mydata)
mydata[mydata$col2== "#N/A"] <- "NA"
na.omit(mydata$col2)

What can I do?

I also tried this:

mydata = mydata[!is.na(mydata)]

But it doesn't work either

score 4 · Answer 1 · answered Feb 27 '18 at 00:49

You should instruct R to treat the string #N/A as NA immediately. The argument na.strings to read.csv tells R what strings to treat as NA.

mydata <- read.csv('file:///C:/Users/file.csv', na.strings = c("", "NA", "#N/A"))
mydata[complete.cases(mydata), ]

score 0 · Answer 2 · answered Feb 27 '18 at 00:34

0

You can do this with the complete.cases function

mydata = mydata[complete.cases(mydata), ]

answered Feb 27 '18 at 00:34

G5W

score 0 · Answer 3 · answered Feb 27 '18 at 00:48

There are multiple issues with your code:

It's usually best to specify stringsAsFactors = FALSE using read.csv (unless you really want factors)
There's no need to use as.data.frame after read.csv, you already have a data frame
In the third line you need a comma before the closing ]
You're replacing with the string "NA", just use NA (no quotes)

To remove rows from data frame mydata, just use na.rm(mydata), not mydata$col2

mydata = read.csv('file:///C:/Users/file.csv', stringsAsFactors = FALSE)
mydata[mydata$col2 == "#N/A", ] <- NA
na.omit(mydata)

3 Answers3