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
[[alternative HTML version deleted]]
You need to use '&' instead of '&&': A shorter version of your code using ifelse: das$danger <- with(das, ifelse(age>65 & bmi>30, 1, 0)) HTH -Christos> -----Original Message----- > From: r-help-bounces at r-project.org > [mailto:r-help-bounces at r-project.org] On Behalf Of Gerard Smits > Sent: Tuesday, January 01, 2008 5:04 PM > To: r-help at r-project.org > Subject: [R] if statement problem > > Hi All, > > I have a small dataset named das (43 cases) in which I am > trying to create a binary outcome (1/0) based on the following code: > > if (das$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 > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > >
You should look for your answer using the help for the if statement
(?"if").
The cond argument should be a scalar (otherwise only the first element
is used).
?"if"
.....
cond: A length-one logical vector that is not 'NA'. Conditions of
length greater than one are accepted with a warning, but only
the first element is used. Other types are coerced to
logical if possible, ignoring any class.
...
The ifelse statement check the condition for each element of your input
(returning
a value with the same shape).
domenico
Gerard Smits wrote:> 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$danger<-0
> attach(das)
> das
>
>
> The following object(s) are masked from das ( position 3 ) :
>
> age bmi day id male sex status
>
> id age sex bmi status day male danger
> 1 33001 35 M 27.5 0 365 1 0
> 2 33002 29 M 34.9 1 22 1 0
> 3 33003 41 F 23.6 0 365 0 0
> 4 33004 55 F 27.0 0 365 0 0
> 5 42001 37 M 39.0 0 365 1 0
> 6 42002 53 M 26.6 1 124 1 0
> 7 42003 46 F 45.4 1 287 0 0
> 8 42004 35 F 36.2 0 365 0 0
> 9 42005 38 F 24.6 0 365 0 0
> 10 42006 58 F 28.0 0 365 0 0
> 11 42007 27 M 25.0 0 365 1 0
> 12 42008 65 F 24.6 0 365 0 0
> 13 42009 25 F 28.0 0 365 0 0
> 14 43001 66 M 27.8 0 365 1 0
> 15 43002 57 F 34.0 0 365 0 0
> 16 43003 45 F 38.1 0 365 0 0
> 17 43004 33 F 53.3 1 62 0 0
> 18 43005 56 F 36.5 0 365 0 0
> 19 43006 31 F 22.4 1 1 0 0
> 20 43007 53 F 32.2 1 21 0 0
> 21 55001 51 M 29.2 0 365 1 0
> 22 55002 33 F 18.7 0 365 0 0
> 23 55003 40 F 30.3 0 365 0 0
> 24 55004 67 M 31.9 0 365 1 0 <- Problem case should
> =1 for danger
> 25 55005 41 F 35.0 0 365 0 0
> 26 55006 44 F 37.3 0 365 0 0
> 27 55007 67 M 28.4 1 1 1 0
> 28 55008 65 F 28.8 0 365 0 0
> 29 55009 76 M 18.8 1 225 1 0
> 30 55010 75 F 21.1 1 39 0 0
> 31 63001 30 F 24.9 0 365 0 0
> 32 63002 36 F 47.2 1 377 0 0
> 33 63003 45 F 32.0 0 365 0 0
> 34 63004 49 F 32.3 0 365 0 0
> 35 63005 41 F 20.2 0 365 0 0
> 36 63006 60 F 28.2 0 365 0 0
> 37 63007 33 F 24.5 0 365 0 0
> 38 63008 36 F 28.4 1 56 0 0
> 39 63009 31 F 22.1 0 365 0 0
> 40 63010 77 M 26.6 1 9 1 0
> 41 63011 41 F 32.0 0 365 0 0
> 42 63012 40 F 38.5 1 92 0 0
> 43 63013 27 M 20.6 0 365 1 0
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
>
Try: das$danger <- with(das, (age > 65) * (bmi > 30)) On Jan 1, 2008 5:03 PM, Gerard Smits <g_smits at verizon.net> wrote:> 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 > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. >