CODEWITHSUNDEEP
rnamissing-data
kkjj
kkjj

Reputation: 31

How to change characters into NA?

I have a census dataset with some missing variables indicated with a ?, When checking for incomplete cases in R it says there are none because R takes the ? as a valid character. Is there any way to change all the ? to NAs? I would like to run multiple imputation using the mice package to fill in the missing data after.

Upvotes: 0

Views: 1754

Answers (2)

Sowmya S. Manian
Sowmya S. Manian

Reputation: 3833

Creating data frame df

df <- data.frame(A=c("?",1,2),B=c(2,3,"?"))
df
#   A B
# 1 ? 2
# 2 1 3
# 3 2 ?

I. Using replace() function

replace(df,df == "?",NA)
#      A    B
# 1 <NA>    2
# 2    1    3
# 3    2 <NA>

II. While importing a file with ?

 data <- read.table("xyz.csv",sep=",",header=T,na.strings=c("?",NA))
 data
 # A  B
 # 1  1 NA
 # 2  2  3
 # 3  3  4
 # 4 NA NA
 # 5 NA NA
 # 6  4  5

Upvotes: 2

ODelibalta
ODelibalta

Reputation: 2244

Data frames. You may need to fiddle with the quotation marks. I have not tested this. 

df[df == "?"] <- NA

Upvotes: 4

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