Determine the number of NA values in a column

Question

I want to count the number of NA values in a data frame column. Say my data frame is called df, and the name of the column I am considering is

Answer 1

I read a csv file from local directory. Following code works for me.

# to get number of which contains na
sum(is.na(df[, c(columnName)]) # to get number of na row

# to get number of which not contains na
sum(!is.na(df[, c(columnName)]) 

#here columnName is your desire column name