Dan wrote:
I have the variables
Pid, x, y, t, d
For 1000 participants, and there are many observations for each
participant.
I'm using an archaic program that uses data in the format:
Pid
X,y
X,y
X,y
END
Pid
X,y
X,y
END
And so on.
I would think that I need to :
loop through for each pid
identify the value of pid
write this value to an outfile
loop through all observations of current pid
extract values for x and y
write x and y values to outfile
write "end" into outfile
I tried this logic, but I can't seem to append info to the outfile...
any ideas?
====================================================================
Interesting puzzle. I assume that -t- is some kind of time variable.
I did not try to guess about -d-.
If these are the data:
. type test1.txt
127
12,13
23,25
26,30
END
128
4,45
7,53
END
I first read each line as a text string.
Next I give a number to each observation, starting afresh after
each "END". The -pid- records get t=0 and the "END" records t=-1.
infix str15 z 1-15 using test1.txt
gen t=0 in 1
replace t=-1 if z=="END"
replace t=t[_n-1]+1 if _n>1 & z!="END"
generate str pid=z if t==0
replace pid=pid[_n-1] if t>0
generate comma = strpos(z,",") if t>0
generate x = real(substr(z,1,comma-1)) if t>0
generate y = real(substr(z,comma+1,.)) if t>0
. list
+------------------------------------+
| z t pid comma x y |
|------------------------------------|
1. | 127 0 127 . . . |
2. | 12,13 1 127 3 12 13 |
3. | 23,25 2 127 3 23 25 |
4. | 26,30 3 127 3 26 30 |
5. | END -1 . . . |
|------------------------------------|
6. | 128 0 128 . . . |
7. | 4,45 1 128 2 4 45 |
8. | 7,53 2 128 2 7 53 |
9. | END -1 . . . |
+------------------------------------+
Finally you can drop the redundant observations and variables:
keep if t>0
keep pid t x y
Hope this helps
Svend
__________________________________________
Svend Juul
Institut for Folkesundhed, Afdeling for Epidemiologi
(Institute of Public Health, Department of Epidemiology)
Vennelyst Boulevard 6
DK-8000 Aarhus C, Denmark
Phone: +45 8942 6090
Home: +45 8693 7796
Email: [email protected]
__________________________________________
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