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st: Selecting maximum values and generating sum variable
From
Catherine Tisch <[email protected]>
To
[email protected]
Subject
st: Selecting maximum values and generating sum variable
Date
Tue, 24 May 2011 14:33:26 +1200
Hello
We have two issues that hopefully you can help us with:
1. We want to select the highest UVI value per ID per day from five
hourly measurements. It is possible for measurements to be zero and in
some instances data is missing. An example of our dataset looks like:
ID Day Hour UVI
1 1 11 5
1 1 12 9
1 1 13 7
1 1 14 3
1 1 15 4
1 2 11 7
1 2 12 8
1 2 13 2
1 2 14 1
1 2 15 .
1 3 11 1
1 3 12 2
1 3 13 1
1 3 14 1
1 3 15 0
2 1 11 .
2 1 12 .
2 1 13 .
2 1 14 .
2 1 15 .
2 2 11 9
2 2 12 10
2 2 13 10
2 2 14 8
2 2 15 6
We would like to create a new variable called 'UVPeak', from the example
above, the output would look like:
ID Day Hour UVI UVIPeak
1 1 11 5 9
1 1 12 9 9
1 1 13 7 9
1 1 14 3 9
1 1 15 4 9
1 2 11 7 8
1 2 12 8 8
1 2 13 2 8
1 2 14 1 8
1 2 15 . 8
1 3 11 1 2
1 3 12 2 2
1 3 13 1 2
1 3 14 1 2
1 3 15 0 2
2 1 11 . .
2 1 12 . .
2 1 13 . .
2 1 14 . .
2 1 15 . .
2 2 11 9 10
2 2 12 10 10
2 2 13 10 10
2 2 14 8 10
2 2 15 6 10
2. We want to know the sum of count of days per ID if UVIPeak is
not missing. We will call this new variable 'SumDays'. From the
example above, the output would look like:
ID Day Hour UVI UVIPeak SumDays
1 1 11 5 9 3
1 1 12 9 9 3
1 1 13 7 9 3
1 1 14 3 9 3
1 1 15 4 9 3
1 2 11 7 8 3
1 2 12 8 8 3
1 2 13 2 8 3
1 2 14 1 8 3
1 2 15 . 8 3
1 3 11 1 2 3
1 3 12 2 2 3
1 3 13 1 2 3
1 3 14 1 2 3
1 3 15 0 2 3
2 1 11 . . 1
2 1 12 . . 1
2 1 13 . . 1
2 1 14 . . 1
2 1 15 . . 1
2 2 11 9 10 1
2 2 12 10 10 1
2 2 13 10 10 1
2 2 14 8 10 1
2 2 15 6 10 1
Can anyone help us create these new variables?
Thanks in advance
Catherine
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