st: RE: Replacing the missing observations

[Nick Cox <n.j.cox@durham.ac.uk>]

This is an FAQ. 

FAQ     . . . . . . . . . . . . . . . . . . . . . . . Replacing missing values
        . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  N. J. Cox
        9/05    How can I replace missing values with previous or
                following nonmissing values or within sequences?
                http://www.stata.com/support/faqs/data/missing.html

In this example 

bysort time (ewdiffret) : replace ewdiffret = ewdiffret[1] 

Note that -replace- is a command (not a function). 

would work. 

Nick 
n.j.cox@durham.ac.uk 

yilmag@rpi.edu

group	time	ewportret	ewdiffret

0	2007m4	.041679	             .
1	2007m4	.0375245	-.0041545
0	2007m5	.0449738	     .
1	2007m5	.0397919	-.0051819
0	2007m6	-.0240277	     .
1	2007m6	-.0188678	.0051599

The variable ewdiffret is the difference in ewportret between group 1 and 
group 0 for each time variable (thanks to Dr. Cox for the help with this). My 
question is how can i now replace all empty cells under the ewdiffret in the 
same month with the single ewdiffret value in that given month. Indeed i have 
too many empty cells in a given month and i want to replace them all with the 
single ewdiffret i have for that month.

For example: I would like to have the first empty cell under ewdiffret equal 
to -.0041545 as the time variable for both is 2007m4 and the second 
empty cell equal to -.0051819 as their time variable is 2007m5. Using too 
many replace functions takes a long time and may cause transcription errors.

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