st: new command -checkfor2-

[Kit Baum <baum@bc.edu>]

Amadou said

Nick, from my point of view, it is easier to type:
nmissing x
than:
count if x == .

Easier, and nmissing (appropriately updated) gives the right answer,  
which count does not...

Note that the count statement as given does not tell you how many  
missing values there are; it tells you how many are equal to ".".  
There are 27 kinds of missing values in Stata, and if you want to  
trap all of them,

count if !(x<.)

is needed:

. tab rep78,missing

     Repair |
Record 1978 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          2        2.70        2.70
          2 |          8       10.81       13.51
          3 |         29       39.19       52.70
          4 |         18       24.32       77.03
          5 |         11       14.86       91.89
          . |          4        5.41       97.30
         .a |          1        1.35       98.65
         .b |          1        1.35      100.00
------------+-----------------------------------
      Total |         74      100.00

. count if rep78 == .
    4

. count if !(rep78<.)
    6


Kit Baum, Boston College Economics
http://ideas.repec.org/e/pba1.html


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