test <- list(NULL) Bert Gunter Nonclinical Biostatistics 467-7374
> -----Original Message----- > From: r-help-boun...@r-project.org > [mailto:r-help-boun...@r-project.org] On Behalf Of Petr PIKAL > Sent: Wednesday, April 29, 2009 8:21 AM > To: ml-r-h...@epigenomics.com > Cc: r-h...@stat.math.ethz.ch; Moumita Das > Subject: Re: [R] if condition doesn't evaluate to True/False > > Hi > > r-help-boun...@r-project.org napsal dne 29.04.2009 17:05:01: > > > see > > ?is.null > > > > e.g. > > if( is.null(sub_grp_whr_cls_data[sbgrp_no, 1]) ) > > { > > your code > > } > > It probably will not work as > > sub_grp_whr_cls_data[sbgrp_no,1]=="NULL" > > implicates that there is character value "NULL". I am not > sure if you can > get NULL as a part of some object. I tried and failed. > See what you get > x<- c(1,2,3, NULL) > > Regards > Petr > > > > > > Moumita Das wrote: > > > Hi friends, > > > Please help me with this bug. > > > > > > *Bug in my code:* > > > > > > In this variable sub_grp_whr_cls_data[sbgrp_no,1] I store > the where > > > clause.every sub group has a where condition linked with it. > > > > > > Database1 > > > > > > > > > Where clause was not found for a particular subgroup, > > > sub_grp_whr_cls_data[sbgrp_no,1] value was NULL > > > > > > So the condition (*sub_grp_whr_cls_data[sbgrp_no,1]=="NULL" || > > > sub_grp_whr_cls_data[sbgrp_no,1]==""*) should evaluate to > TRUE ,but it > > > evaluated to NA > > > > > > So the if block where I used the the condition threw error > > > > > > If(*sub_grp_whr_cls_data[sbgrp_no,1]=="NULL" || > > > sub_grp_whr_cls_data[sbgrp_no,1]==""*) > > > > > > i.e if(NA) > > > > > > Error:-- > > > > > > Error in if (sub_grp_whr_cls_data[sbgrp_no, 1] == "NULL" || > > > sub_grp_whr_cls_data[sbgrp_no, : > > > > > > missing value where TRUE/FALSE needed > > > > > > Comments:-- but when there 's no where clause value the condition > > > (sub_grp_whr_cls_data[sbgrp_no,1]=="NULL" > > > ||sub_grp_whr_cls_data[sbgrp_no,1]=="") should > automatically evaluate > to * > > > TRUE* > > > > > > > > > > > > Database2 > > > > > > Where clause was found for a particular subgroup > > > > > > The condition (sub_grp_whr_cls_data[sbgrp_no,1]=="NULL" > > > ||sub_grp_whr_cls_data[sbgrp_no,1]=="") evaluated to FALSE > > > > > > So if (sub_grp_whr_cls_data[sbgrp_no,1]=="NULL" > > > ||sub_grp_whr_cls_data[sbgrp_no,1]=="") is > > > > > > If (FALSE) ,control goes to the else part. > > > > > > This is exactly what is expected of the program. > > > > > > *QUERY:-- **If the condition evaluates to FALSE when a where > condition is > > > available why doesn't it evaluate to TRUE when a where condition > available > > > is NULL or no where condition is available.* > > > > > > Here I have taken the example of two databases where I > tried to get > the > > > where clause for subgroup 1.In case of Database1 it was > not available > in > > > case of Databse2 it was available.But the problem may > appear for the > same > > > database also, when where clause is available for say one > subgroup and > not > > > for the other. > > > > > > > > > > > > > -------------------------------------------------------------- > ---------- > > > > > > ______________________________________________ > > > R-help@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. > > > > > > -- > > Matthias Burger Project Manager/ Biostatistician > > Epigenomics AG Kleine Praesidentenstr. 1 10178 Berlin, Germany > > phone:+49-30-24345-0 fax:+49-30-24345-555 > > http://www.epigenomics.com matthias.bur...@epigenomics.com > > -- > > Epigenomics AG Berlin Amtsgericht Charlottenburg HRB 75861 > > Vorstand: Geert Nygaard (CEO/Vorsitzender) > > Oliver Schacht PhD (CFO) > > Aufsichtsrat: Prof. Dr. Dr. hc. Rolf Krebs (Chairman/Vorsitzender) > > > > ______________________________________________ > > R-help@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. > > ______________________________________________ > R-help@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. > ______________________________________________ R-help@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.