Hi All,

I have a small dataset named das  (43 cases) in which I am trying to 
create a binary outcome (1/0) based on the following code:

if (das$age>65 && das$bmi>30) {das$danger<-1} else das$danger<-0

I am setting a flag called 'danger' to 1 of the subject is over 65 
and has a BMI > 30.

I find that my statement evaluates the first record in the data.frame 
and then carries that assignment for all. I detected this as I played 
around with the values and found that the T/F status of the first 
record was always carried dowqn. I have gotten this to work with an 
elseif construction, but would like to know what is happening here.

Thanks,

Gerard

Using: Windows Vista and R 2.61


Code and output:

das<- sasxport.get("c:\\personal\\r\\das.xpt")
if (das$age>65 && das$bmi>30) {das$danger<-1} else das$danger<-0
attach(das)
das


         The following object(s) are masked from das ( position 3 ) :

          age bmi day id male sex status

       id age sex  bmi status day male danger
1  33001  35   M 27.5      0 365    1      0
2  33002  29   M 34.9      1  22    1      0
3  33003  41   F 23.6      0 365    0      0
4  33004  55   F 27.0      0 365    0      0
5  42001  37   M 39.0      0 365    1      0
6  42002  53   M 26.6      1 124    1      0
7  42003  46   F 45.4      1 287    0      0
8  42004  35   F 36.2      0 365    0      0
9  42005  38   F 24.6      0 365    0      0
10 42006  58   F 28.0      0 365    0      0
11 42007  27   M 25.0      0 365    1      0
12 42008  65   F 24.6      0 365    0      0
13 42009  25   F 28.0      0 365    0      0
14 43001  66   M 27.8      0 365    1      0
15 43002  57   F 34.0      0 365    0      0
16 43003  45   F 38.1      0 365    0      0
17 43004  33   F 53.3      1  62    0      0
18 43005  56   F 36.5      0 365    0      0
19 43006  31   F 22.4      1   1    0      0
20 43007  53   F 32.2      1  21    0      0
21 55001  51   M 29.2      0 365    1      0
22 55002  33   F 18.7      0 365    0      0
23 55003  40   F 30.3      0 365    0      0
24 55004  67   M 31.9      0 365    1      0 <- Problem case should 
=1 for danger
25 55005  41   F 35.0      0 365    0      0
26 55006  44   F 37.3      0 365    0      0
27 55007  67   M 28.4      1   1    1      0
28 55008  65   F 28.8      0 365    0      0
29 55009  76   M 18.8      1 225    1      0
30 55010  75   F 21.1      1  39    0      0
31 63001  30   F 24.9      0 365    0      0
32 63002  36   F 47.2      1 377    0      0
33 63003  45   F 32.0      0 365    0      0
34 63004  49   F 32.3      0 365    0      0
35 63005  41   F 20.2      0 365    0      0
36 63006  60   F 28.2      0 365    0      0
37 63007  33   F 24.5      0 365    0      0
38 63008  36   F 28.4      1  56    0      0
39 63009  31   F 22.1      0 365    0      0
40 63010  77   M 26.6      1   9    1      0
41 63011  41   F 32.0      0 365    0      0
42 63012  40   F 38.5      1  92    0      0
43 63013  27   M 20.6      0 365    1      0

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