R help - Aug 2004 - lapply problem

R-help,

I wish to replace NULL elements(or missing) in the following list
:
> z2
$cod
    mean       sd 
62.56190 12.65452 

$haddock
    mean       sd 
36.61490 11.50365 

$ling
    mean       sd 
86.17949 20.43587 

$saithe
     mean        sd 
50.275847  5.453606 

$whiting
NULL

$"norway pout"
     mean        sd 
13.739623  1.393104 

$"great silver smelt"
     mean        sd 
25.600000  1.549193 

$"norway hadock"
     mean        sd 
24.685225  3.902989

If I use 
lapply(z2,function(x) ifelse(is.null(x),0,as.numeric(x))) 

I get 
> z2
$cod
[1] 62.5619

$haddock
[1] 36.6149

$ling
[1] 86.17949

$saithe
[1] 50.27585

$whiting
[1] 0

$"norway pout"
[1] 13.73962

$"great silver smelt"
[1] 25.6

$"norway hadock"
[1] 24.68522

i.e,only the first element in z2

And if I use
> z2<-lapply(msd.sumin.Z2S,function(x) ifelse(is.na(x),0,x))
Warning message: 
is.na() applied to non-(list or vector) in: is.na(x) 
> z2
$cod
    mean       sd 
62.56190 12.65452 

$haddock
    mean       sd 
36.61490 11.50365 

$ling
    mean       sd 
86.17949 20.43587 

$saithe
     mean        sd 
50.275847  5.453606 

$whiting
logical(0)

$"norway pout"
     mean        sd 
13.739623  1.393104 

$"great silver smelt"
     mean        sd 
25.600000  1.549193 

$"norway hadock"
     mean        sd 
24.685225  3.902989 



which cannot be coreced to data frame(which is my aim)

How can it be resolve??

Thank you


Luis Ridao Cruz
Fiskiranns??knarstovan
N??at??n 1
P.O. Box 3051
FR-110 T??rshavn
Faroe Islands
Phone:             +298 353900
Phone(direct): +298 353912
Mobile:             +298 580800
Fax:                 +298 353901
E-mail:              luisr at frs.fo
Web:                www.frs.fo

Hi Luis,

try to use,


lapply(z2, function(x) if(is.null(x)) c(0,0) else x)


I hope this helps.

Best,
Dimitris

----
Dimitris Rizopoulos
Doctoral Student
Biostatistical Centre
School of Public Health
Catholic University of Leuven

Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: +32/16/396887
Fax: +32/16/337015
Web: http://www.med.kuleuven.ac.be/biostat/
     http://www.student.kuleuven.ac.be/~m0390867/dimitris.htm



----- Original Message ----- 
From: "Luis Rideau Cruz" <Luisr at frs.fo>
To: <r-help at stat.math.ethz.ch>
Sent: Friday, August 13, 2004 1:40 PM
Subject: [R] lapply problem

> R-help,
>
> I wish to replace NULL elements(or missing) in the following list :
> > z2
> $cod
>     mean       sd
> 62.56190 12.65452
>
> $haddock
>     mean       sd
> 36.61490 11.50365
>
> $ling
>     mean       sd
> 86.17949 20.43587
>
> $saithe
>      mean        sd
> 50.275847  5.453606
>
> $whiting
> NULL
>
> $"norway pout"
>      mean        sd
> 13.739623  1.393104
>
> $"great silver smelt"
>      mean        sd
> 25.600000  1.549193
>
> $"norway hadock"
>      mean        sd
> 24.685225  3.902989
>
> If I use
> lapply(z2,function(x) ifelse(is.null(x),0,as.numeric(x)))
>
> I get
>
> > z2
> $cod
> [1] 62.5619
>
> $haddock
> [1] 36.6149
>
> $ling
> [1] 86.17949
>
> $saithe
> [1] 50.27585
>
> $whiting
> [1] 0
>
> $"norway pout"
> [1] 13.73962
>
> $"great silver smelt"
> [1] 25.6
>
> $"norway hadock"
> [1] 24.68522
>
> i.e,only the first element in z2
>
> And if I use
>
> > z2<-lapply(msd.sumin.Z2S,function(x) ifelse(is.na(x),0,x))
> Warning message:
> is.na() applied to non-(list or vector) in: is.na(x)
> > z2
> $cod
>     mean       sd
> 62.56190 12.65452
>
> $haddock
>     mean       sd
> 36.61490 11.50365
>
> $ling
>     mean       sd
> 86.17949 20.43587
>
> $saithe
>      mean        sd
> 50.275847  5.453606
>
> $whiting
> logical(0)
>
> $"norway pout"
>      mean        sd
> 13.739623  1.393104
>
> $"great silver smelt"
>      mean        sd
> 25.600000  1.549193
>
> $"norway hadock"
>      mean        sd
> 24.685225  3.902989
>
>
>
> which cannot be coreced to data frame(which is my aim)
>
> How can it be resolve??
>
> Thank you
>
>
> Luis Ridao Cruz
> Fiskiranns??knarstovan
> N??at??n 1
> P.O. Box 3051
> FR-110 T??rshavn
> Faroe Islands
> Phone:             +298 353900
> Phone(direct): +298 353912
> Mobile:             +298 580800
> Fax:                 +298 353901
> E-mail:              luisr at frs.fo
> Web:                www.frs.fo
>
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide!
http://www.R-project.org/posting-guide.html

"Luis Rideau Cruz" <Luisr at frs.fo> writes:
> R-help,
> 
> I wish to replace NULL elements(or missing) in the following list :
...
> If I use 
> lapply(z2,function(x) ifelse(is.null(x),0,as.numeric(x))) 
...
> i.e,only the first element in z2
ifelse(....) gives a result that is the same length as the condition,
and is.null(x) has length 1. You want

if (is.null(x)) 0 else as.numeric(x)

-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)             FAX: (+45) 35327907