[R] Summary tables of large datasets including character and numerical variables

John Kane jrkrideau at yahoo.ca
Tue Dec 27 13:36:22 CET 2011

A function like the one below will give you the class and number of valid
entries for a dataset.  At sample data set would help determine if it works.
It works on a simple data set I created and one from the ggplot2 package but it is
not really tested.

With your data set as df1 something like 
xx <- msum(df1) 
should supply you with the information.

Other than that I really don't see why Hmisc :: describe() would not give you
most or all the information you seek with the exception of the "length"thing which
really don't understand. Actually I believe describe() will give you 
the number of non-NA entries for a variable.

msum <- function(dat1) {
nams <- c("class", "non-missing")
cl <- lapply(dat1, class)
nas <-colSums(!is.na(dat1))
mysum <- data.frame(unlist(cl), unlist(nas))
names(mysum) <- nams
mysum <- mysum


----- Original Message -----
From: sparandekar <sparandekar at yahoo.com.ar>
To: r-help at r-project.org
Sent: Monday, December 26, 2011 5:44:53 AM
Subject: [R] Summary tables of large datasets including character and numerical variables

Hello !

I am attempting to switch from being a long time SAS user to R, and would
really appreciate a bit of help ! The first thing I do in getting a large
dataset (thousands of obervations and hundreds of variables) is to run a SAS
command PROC CONTENTS VARNUM command - this provides me a table with the
name of each variable, its type and length;  then I run a PROC MEANS - for
numerical variables it gives me a table with the number of non-missing
values, min, max, mean and std. dev.  My data usually has errors and this
first step helps me to spot the errors and 'clean' the dataset.

The 'summary' function in R and other function as part of Hmisc or Psych
package do not work for me. 

How can I get a table from an R data.frame that has the following structure
(header row and example).

Rowname  Character/Integer  Length   Non-Missing    Minimum          
Maximum              Mean                   SD

HHID            Integer                       12            32,344              
114455007701   514756007812       2.345 x 10^10    1.456 x 10^10
Head            Character                   38            24,566                      
-                                   -                         -                          

Thank you very much. 

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