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Re: st: Placing a non-missing value at beginning of a block


From   Jeph Herrin <junk@spandrel.net>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Placing a non-missing value at beginning of a block
Date   Wed, 10 Dec 2008 13:05:23 -0500


I'm a little confused because in the second set of data
below, the -pvalues- have moved but the -n-s have not, which
I think may not be what you want, but we'll do it anyway.

 gen group=_n
 sort n
 replace group=group[_n-1] if _n>1&!(mi(pvalue)&!mi(pvalue[_n-1]))

this creates a variable -group- which is constant for each of your
groups. Then, to shift the pvalue to the top of the group:

 bys group (n) : replace pvalue[1]=pvalue[_N]
 bys group (n) : replace pvalue[_N]=.

hth,
Jeph


Thomas Speidel wrote:
I am trying to create a spreadsheet ready table from within Stata and need to do some data management in order to go from this:

n    pvalue
1    .
2    .
3    .
4    .
5    0.151
6    .
7    .
8    .
9    .
10    0.000
11    .
12    .
13    .
14    .
15    0.146
16    .
17    .
18    .
19    .
20    .
21    0.001
...

To this:

n    pvalue
1    0.151
2    .
3    .
4    .
5    .
6    0.000
7    .
8    .
9    .
10    .
11    0.146
12    .
13    .
14    .
15    .
16    0.001
17    .
18    .
19    .
20    .
21    .
...

Notice that the blocks are not constant (some are 5, some are 6 etc. -this is just a portion of the data-). My difficulty lies in the fact that there is no natural grouping variable. I tried a mixture of subscripting and sequence generating commands, but did not get too far. The crucial part is that I need to place the non-missing pvalue at the beginning of the block, while right now it is at the end.

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