[R] Bug in colnames of data.frames?
Hi, I am using R 1.9.1 on on i686 PC with SuSE Linux 9.0. I have a data.frame, e.g.: myData - data.frame( var1 = c( 1:4 ), var2 = c (5:8 ) ) If I add a new column by myData$var3 - myData[ , var1 ] + myData[ , var2 ] everything is fine, but if I omit the commas: myData$var4 - myData[ var1 ] + myData[ var2 ] the name shown above the 4th column is not var4: myData var1 var2 var3 var1 11566 22688 337 10 10 448 12 12 but names() and colnames() return the expected name: names( myData ) [1] var1 var2 var3 var4 colnames( myData ) [1] var1 var2 var3 var4 And it is even worse: I am not able to change the name shown above the 4th column: names( myData )[ 4 ] - var5 myData var1 var2 var3 var1 11566 22688 337 10 10 448 12 12 I guess that this is a bug, isn't it? Arne __ [EMAIL PROTECTED] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
Re: [R] Bug in colnames of data.frames?
Arne Henningsen wrote: Hi, I am using R 1.9.1 on on i686 PC with SuSE Linux 9.0. I have a data.frame, e.g.: myData - data.frame( var1 = c( 1:4 ), var2 = c (5:8 ) ) If I add a new column by myData$var3 - myData[ , var1 ] + myData[ , var2 ] everything is fine, but if I omit the commas: myData$var4 - myData[ var1 ] + myData[ var2 ] This bug is the user ... ;-) Type: str(myData) `data.frame': 4 obs. of 3 variables: $ var1: int 1 2 3 4 $ var2: int 5 6 7 8 $ var4:`data.frame': 4 obs. of 1 variable: ..$ var1: int 6 8 10 12 Aha! You have created a data.frame consisting of one column! What you mean really mean is myData$var5 - myData[[ var1 ]] + myData[[ var2 ]] Uwe Ligges the name shown above the 4th column is not var4: myData var1 var2 var3 var1 11566 22688 337 10 10 448 12 12 but names() and colnames() return the expected name: names( myData ) [1] var1 var2 var3 var4 colnames( myData ) [1] var1 var2 var3 var4 And it is even worse: I am not able to change the name shown above the 4th column: names( myData )[ 4 ] - var5 myData var1 var2 var3 var1 11566 22688 337 10 10 448 12 12 I guess that this is a bug, isn't it? Arne __ [EMAIL PROTECTED] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html __ [EMAIL PROTECTED] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
Re: [R] Bug in colnames of data.frames?
Arne Henningsen [EMAIL PROTECTED] writes: Hi, I am using R 1.9.1 on on i686 PC with SuSE Linux 9.0. I have a data.frame, e.g.: myData - data.frame( var1 = c( 1:4 ), var2 = c (5:8 ) ) If I add a new column by myData$var3 - myData[ , var1 ] + myData[ , var2 ] everything is fine, but if I omit the commas: myData$var4 - myData[ var1 ] + myData[ var2 ] the name shown above the 4th column is not var4: myData var1 var2 var3 var1 11566 22688 337 10 10 448 12 12 but names() and colnames() return the expected name: names( myData ) [1] var1 var2 var3 var4 colnames( myData ) [1] var1 var2 var3 var4 And it is even worse: I am not able to change the name shown above the 4th column: names( myData )[ 4 ] - var5 myData var1 var2 var3 var1 11566 22688 337 10 10 448 12 12 I guess that this is a bug, isn't it? Nope: str(myData) `data.frame': 4 obs. of 4 variables: $ var1: int 1 2 3 4 $ var2: int 5 6 7 8 $ var3: int 6 8 10 12 $ var4:`data.frame': 4 obs. of 1 variable: ..$ var1: int 6 8 10 12 It's slightly peculiar, but if a column of a data frame is itself a rectangular structure (data frame or matrix), then the innermost names are used. Cf. myData[,var4] - cbind(xyzzy=5:2) myData var1 var2 var3 xyzzy 1156 5 2268 4 337 10 3 448 12 2 Arguably, one might prefer var1 var2 var3 var4 xyzzy 1156 5 2268 4 337 10 3 448 12 2 or something like that, but it's hardly a bug. -- O__ Peter Dalgaard Blegdamsvej 3 c/ /'_ --- Dept. of Biostatistics 2200 Cph. N (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~ - ([EMAIL PROTECTED]) FAX: (+45) 35327907 __ [EMAIL PROTECTED] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
Re: [R] Bug in colnames of data.frames? -- NOT
This is not a bug, and BTW data frames have names not colnames. As I have said already today, don't confuse the printed repesentation of an object with the object itself. On Tue, 17 Aug 2004, Arne Henningsen wrote: I am using R 1.9.1 on on i686 PC with SuSE Linux 9.0. I have a data.frame, e.g.: myData - data.frame( var1 = c( 1:4 ), var2 = c (5:8 ) ) If I add a new column by myData$var3 - myData[ , var1 ] + myData[ , var2 ] everything is fine, but if I omit the commas: myData$var4 - myData[ var1 ] + myData[ var2 ] the name shown above the 4th column is not var4: myData var1 var2 var3 var1 11566 22688 337 10 10 448 12 12 but names() and colnames() return the expected name: names( myData ) [1] var1 var2 var3 var4 colnames( myData ) [1] var1 var2 var3 var4 And it is even worse: I am not able to change the name shown above the 4th column: names( myData )[ 4 ] - var5 myData var1 var2 var3 var1 11566 22688 337 10 10 448 12 12 I guess that this is a bug, isn't it? No. Take a look at the fourth column more carefully. myData[4] var1 16 28 3 10 4 12 class(myData[4]) [1] data.frame You included a single-column data frame in your data frame. -- Brian D. Ripley, [EMAIL PROTECTED] Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UKFax: +44 1865 272595 __ [EMAIL PROTECTED] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
Re: [R] Bug in colnames of data.frames?
On Tue, 2004-08-17 at 09:01, Arne Henningsen wrote: Hi, I am using R 1.9.1 on on i686 PC with SuSE Linux 9.0. I have a data.frame, e.g.: myData - data.frame( var1 = c( 1:4 ), var2 = c (5:8 ) ) If I add a new column by myData$var3 - myData[ , var1 ] + myData[ , var2 ] everything is fine, but if I omit the commas: myData$var4 - myData[ var1 ] + myData[ var2 ] the name shown above the 4th column is not var4: myData var1 var2 var3 var1 11566 22688 337 10 10 448 12 12 but names() and colnames() return the expected name: names( myData ) [1] var1 var2 var3 var4 colnames( myData ) [1] var1 var2 var3 var4 And it is even worse: I am not able to change the name shown above the 4th column: names( myData )[ 4 ] - var5 myData var1 var2 var3 var1 11566 22688 337 10 10 448 12 12 I guess that this is a bug, isn't it? Arne Here is a hint: # This returns an integer vector str(myData[ , var1 ] + myData[ , var2 ]) int [1:4] 6 8 10 12 # This returns a data.frame str(myData[ var1 ] + myData[ var2 ]) `data.frame': 4 obs. of 1 variable: $ var1: int 6 8 10 12 str(myData) `data.frame': 4 obs. of 5 variables: $ var1: int 1 2 3 4 $ var2: int 5 6 7 8 $ var3: int 6 8 10 12 $ var4:`data.frame': 4 obs. of 1 variable: ..$ var1: int 6 8 10 12 Take a look at the details, value and coercion sections of ?.data.frame HTH, Marc Schwartz __ [EMAIL PROTECTED] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
Re: [R] Bug in colnames of data.frames?
On Tue, 2004-08-17 at 09:34, Marc Schwartz wrote: Take a look at the details, value and coercion sections of ?.data.frame This must be my week for typos. That should be: ?[.data.frame (in ESS) or ?[.data.frame (otherwise) Marc __ [EMAIL PROTECTED] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
Re: [R] Bug in colnames of data.frames?
On Tue, 17 Aug 2004, Arne Henningsen wrote: Thank you for all your answers! I agree with you that it is not a bug. My mistake was that I thought that a data frame is similar to a matrix, but as ?data.frame says they ... share many of the properties of matrices and of lists. ... I think the current presentation myData var1 var2 var3 xyzzy 1156 5 2268 4 337 10 3 448 12 2 is confusing because it is not directly (without another command like str()) apparent why myData[[ var1 ]] works fine while myData[[ xyzzy ]] does not. In some ways it is a bug -- in the documentation, print.data.frame, or format.data.frame Consider assigning a wider dataframe to var4: myData-data.frame(matrix(1:12,4),var4=I(data.frame(xyzzy=5:2,plugh=1:4))) myData # error class(myData[[var4]])-data.frame myData # gives indications of sub-variables by var.xyzzy, var.plugh myData[[var4.plugh]] # NULL myData[[var4]][[plugh]] str(myData) By the way, is there a way of making such an assignment in one step without the I() class() hack? dave -- Dave Forrest [EMAIL PROTECTED](804)684-7900w [EMAIL PROTECTED] (804)642-0662h http://maplepark.com/~drf5n/ __ [EMAIL PROTECTED] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
