如何计算R中表格的每一列中的元素

Question

i have a data set which look like this (actually it has >50 columns)

data <- read.csv("sample.csv")

subject gender  age type    satisfation     agree 
1   f   22  a   yes yes
2   f   23  b   no  yes 
3   f   21  b       no
4   m   24  c   yes yes 
5   f   22  b   no  yes
6   m       a   yes yes 
7       25  c   yes no
8   m   21  b   no  yes 
9   f   23  c   yes yes

I would like to count the elements in each column (don't count NA) and export the result as the layout below

subject gender  age type    satisfation     agree 
9   8   8   9   8   9

i wrote a script to count

counting <- function(x) {
  for(i in 1:length(data)) {
     data <- length(which(!is.na(x$i)))
      print(data)
  }
  return(data)
}   
counting(data)

i didn't work out as it gave all 0.

dput(head(data, 9))

structure(list(subject = 1:9, gender = structure(c(2L, 2L, 2L, 
3L, 2L, 3L, 1L, 3L, 2L), .Label = c("", "f", "m"), class = "factor"), 
    age = c(22L, 23L, 21L, 24L, 22L, NA, 25L, 21L, 23L), type = structure(c(1L, 
    2L, 2L, 3L, 2L, 1L, 3L, 2L, 3L), .Label = c("a", "b", "c"
    ), class = "factor"), satisfation = structure(c(3L, 2L, 1L, 
    3L, 2L, 3L, 3L, 2L, 3L), .Label = c("", "no", "yes"), class = "factor"), 
    agree = structure(c(2L, 3L, 1L, 3L, 2L, 3L, 1L, 3L, 2L), .Label = c("no", 
    "yes", "yes "), class = "factor"), time = c(23L, 54L, 67L, 
    324L, 87L, 12L, 756L, 34L, 98L), day = c(1L, 3L, 2L, 5L, 
    7L, 4L, 3L, 1L, 4L)), .Names = c("subject", "gender", "age", 
"type", "satisfation", "agree", "time", "day"), row.names = c(NA, 
9L), class = "data.frame")

Is there any recommendation for the script, plz?

Thank you all in advance!

Answer 1

Assuming you have handled NA then simply use colSums ,

colSums(!is.na(df))
#    subject    gender       age       type   satisfation    agree      time        day 
#          9      9           8           9           9       9          9           9 

Adding @DavidArenburg suggestion so as to overcome any NA trouble,

colSums(!is.na(df) | df != "", na.rm = TRUE)

Answer 2

When I load your table into R there are just blank spaces instead of NAs. So when you read your .csv file, specify how NAs are coded. It looks like they are coded as "" or maybe " ".

After you get the NAs, you can run this code. Assume your table is called df .

counts <- apply(df, 2, function(x) length(na.omit(x)))

Or, as @JasonAizkalns suggests:

data <- read.csv("sample.csv", na.strings = "") 
sapply(data, function(x) sum(!is.na(x))