How do you change specific values (like 7) in a column to NA in R? -

i working on project did not know recorded 7 in column , refused answer recorded 9. trying find easy way convert these values na.

you can use simple logic assign na, in following simple example.

column <- c(1,2,1,3,7,7,1,2,9) column[column %in% c(7,9)] <- na  > column [1]  1  2  1  3 na na  1  2 na 

basically, can operate on column of data frame using $ operator. treats column vector. using logical operator on vector returns vector of true or false back, can used select elements of vector change na.

i caution might not want that. using na instead of values in r can have annoying side effects because operation against na returns na.

edited add: per gregor, should mention data frame allows select single columns out of using $ operator. instance, in data frame df.example, if columns a, b, , c, df.example$a extract column vector. in contrast, [ operator not create vector subsets, , used select multiple columns of data frame smaller data frame. instance, given our example data frame, select columns , b different data frame using df.example[c("a","b")]. more guidance, trying running help('[') in r.