How to customize the display format of a variable

Data are often stored in a way that is accurate but difficult to read. Dates are a special case and we will discuss them later. But numbers are often stored with many decimal places of accuracy, and we would like to make them easier to view while retaining that accuracy. We can do this by customizing the display format of those variables.

Let's begin by opening and describing an example dataset from the Stata website.

. use https://www.stata.com/users/youtube/rawdata.dta, clear

. describe

Contains data from https://www.stata.com/users/youtube/rawdata.dta
 Observations:         1,268                  Fictitious data based on the
                                                National Health and Nutrition
                                                Examination Survey
    Variables:            10                  6 Jul 2016 11:17
                                              (_dta has notes)


Variable      Storage   Display    Value                                        
    name         type    format    label      Variable label                    

id              str6    %9s                   Identification Number
age             byte    %9.0g                 
sex             byte    %9.0g                 Sex
race            str5    %9s                   Race
height          float   %9.0g                 height (cm)
weight          float   %9.0g                 weight (kg)
sbp             int     %9.0g                 Systolic blood pressure (mm/Hg)
dbp             int     %9.0g                 Diastolic blood pressure (mm/Hg)
chol            str3    %9s                   serum cholesterol (mg/dL)
dob             str18   %18s                  

Sorted by: id

The variable label for weight tells us that it is measured in kilograms. Let's list the first 10 observations in the variable weight.

. list weight in 1/10


     
 weight 
  1. 
  83.69 
  2. 
  83.69 
  3. 
  64.98 
  4. 
  81.65 
  5. 
  92.65 
  6. 
  68.95 
  7. 
  54.55 
  8. 
  66.57 
  9. 
  102.4 
 10. 
  75.52 

Weight is measured with two digits to the right of the decimal. But we don't want to see those decimal values when viewing weight, so let's change the display format to show only the whole numbers.

. format %6.0f weight

Display formats begin with the % character, which is followed by the number of characters to display. The digit after the decimal specifies the number of digits to display to the right of the decimal, which, in this example, is 0. Let's list the data for weight again.

. list weight in 1/10


     
 weight 
  1. 
     84 
  2. 
     84 
  3. 
     65 
  4. 
     82 
  5. 
     93 
  6. 
     69 
  7. 
     55 
  8. 
     67 
  9. 
    102 
 10. 
     76 

We don't see the digits to the right of the decimal anymore. The digits are still in the dataset, and we haven't lost any information. We have simply changed the way the data are displayed.

You can do many things with format, and you can learn more by typing help format.

Now we can save our dataset.

. save mydata
file mydata.dta saved

You can watch a demonstration of these commands by clicking on the link to the YouTube video below. You can read more about these commands by clicking on the links to the Stata manual entries below.

See it in action

Watch Data management: How to change the display format of a variable.