Dear Sirs, I am Professor at Indira Gandhi Krishi Vishwavidyalaya, Raipur, Chhattisgarh, India.
While taking classes, I found the *by() *function producing following error when I use FUN=mean or median and some other functions, however, FUN=summary works. Given below is the output of the example I used on a built-in dataset "mtcars", along with error message reproduced herewith: > by(data=mtcars, INDICES=list(mtcars$am), FUN=mean) : 0 [1] NA ------------------------------------------------------------ : 1 [1] NA Warning messages: 1: In mean.default(data[x, , drop = FALSE], ...) : argument is not numeric or logical: returning NA 2: In mean.default(data[x, , drop = FALSE], ...) : argument is not numeric or logical: returning NA However, the same by() function works for FUN=summary, given below is the output: > by(data=mtcars, INDICES=list(mtcars$am), FUN=summary) : 0 mpg cyl disp hp Min. :10.40 Min. :4.000 Min. :120.1 Min. : 62.0 1st Qu.:14.95 1st Qu.:6.000 1st Qu.:196.3 1st Qu.:116.5 Median :17.30 Median :8.000 Median :275.8 Median :175.0 Mean :17.15 Mean :6.947 Mean :290.4 Mean :160.3 3rd Qu.:19.20 3rd Qu.:8.000 3rd Qu.:360.0 3rd Qu.:192.5 Max. :24.40 Max. :8.000 Max. :472.0 Max. :245.0 drat wt qsec vs am Min. :2.760 Min. :2.465 Min. :15.41 Min. :0.0000 Min. :0 1st Qu.:3.070 1st Qu.:3.438 1st Qu.:17.18 1st Qu.:0.0000 1st Qu.:0 Median :3.150 Median :3.520 Median :17.82 Median :0.0000 Median :0 Mean :3.286 Mean :3.769 Mean :18.18 Mean :0.3684 Mean :0 3rd Qu.:3.695 3rd Qu.:3.842 3rd Qu.:19.17 3rd Qu.:1.0000 3rd Qu.:0 Max. :3.920 Max. :5.424 Max. :22.90 Max. :1.0000 Max. :0 gear carb Min. :3.000 Min. :1.000 1st Qu.:3.000 1st Qu.:2.000 Median :3.000 Median :3.000 Mean :3.211 Mean :2.737 3rd Qu.:3.000 3rd Qu.:4.000 Max. :4.000 Max. :4.000 ------------------------------------------------------------ : 1 mpg cyl disp hp drat Min. :15.00 Min. :4.000 Min. : 71.1 Min. : 52.0 Min. :3.54 1st Qu.:21.00 1st Qu.:4.000 1st Qu.: 79.0 1st Qu.: 66.0 1st Qu.:3.85 Median :22.80 Median :4.000 Median :120.3 Median :109.0 Median :4.08 Mean :24.39 Mean :5.077 Mean :143.5 Mean :126.8 Mean :4.05 3rd Qu.:30.40 3rd Qu.:6.000 3rd Qu.:160.0 3rd Qu.:113.0 3rd Qu.:4.22 Max. :33.90 Max. :8.000 Max. :351.0 Max. :335.0 Max. :4.93 wt qsec vs am gear Min. :1.513 Min. :14.50 Min. :0.0000 Min. :1 Min. :4.000 1st Qu.:1.935 1st Qu.:16.46 1st Qu.:0.0000 1st Qu.:1 1st Qu.:4.000 Median :2.320 Median :17.02 Median :1.0000 Median :1 Median :4.000 Mean :2.411 Mean :17.36 Mean :0.5385 Mean :1 Mean :4.385 3rd Qu.:2.780 3rd Qu.:18.61 3rd Qu.:1.0000 3rd Qu.:1 3rd Qu.:5.000 Max. :3.570 Max. :19.90 Max. :1.0000 Max. :1 Max. :5.000 carb Min. :1.000 1st Qu.:1.000 Median :2.000 Mean :2.923 3rd Qu.:4.000 Max. :8.000 > I am using the latest version of *R-3.2.4 on Windows*, however, this error is being generated in the previous version too, Hope this reporting will get serious attention in debugging. With best regards, Dr. A.K. Singh Head, Department of Agril. Statistics Indira Gandhi Krishi Vishwavidyalaya, Raipur Chhattisgarh, India, PIN-492012 Mobile: +919752620740 Email: akhileshsingh.i...@gmail.com [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.