CODEWITHSUNDEEP
rna
user2120870
user2120870

Reputation: 869

Input NAs in a dataframe

I would like to input NAs in a dataframe setting a specific number of rows. Let´s suppose that I would like two rows of NAs

This is my input:

df <- "col1 col2 col3"
df <- read.table(text=df, header=T)

> ncol(df)
[1] 3

And below is my expected output

dfout <- "col1 col2 col3
          NA    NA   NA
          NA    NA   NA"
dfout <- read.table(text=dfout, header=T)

> ncol(dfout)
[1] 3

> nrow(dfout)
[1] 2

Any ideas? Thank you

Upvotes: 1

Views: 92

Answers (2)

desertnaut
desertnaut

Reputation: 60321

What about

dfout <- df
# dfout[c(1,2),] <- c(NA, NA, NA) # not necessary - see comment below
dfout[c(1,2),] <- NA
dfout
#   col1 col2 col3
# 1   NA   NA   NA
# 2   NA   NA   NA

by setting the dfout row indices in the second line, you should be able to do the job.

Upvotes: 2

akrun
akrun

Reputation: 886938

We replicate the 'NA' 2 times i.e the nrows required, convert to list, replicate '3' based on the number of substrings in 'df', set the names of the 'list' with 'df' after extracting the individual elements using scan and convert to 'data.frame'.

data.frame(setNames(rep(list(rep(NA,2)),3), scan(text=df, sep='', what='')))

Converting the one line to small chunks for better explanation.

v1 <- scan(text=df, sep='', what='')#extract individual elements
nR <- 2 #specify the nrows
nC <- length(v1) #ncols based on the length of 'v1'
lst <- rep(list(rep(NA, nR)), nC) #replicate NA.
names(lst) <- v1 #set the 'names' of 'list'
data.frame(lst)  #convert to 'data.frame'

data

df <- "col1 col2 col3"

Upvotes: 2

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