Hi, ----- Original Message ----- From: "Mike Campana" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Thursday, March 11, 2004 12:20 PM Subject: [R] failure in simple calculation!!
> Hello > > I have a dataframe, at least I think I created it by using: > > DELTA <- as.data.frame(DELTA) > > The dataframe has 2 columns made of numbers("data" and "delta") > > If I use DELTA$delta + 12 > I get a sequence of NA Warning message: > "+" not meaningful for factors in: Ops.factor(DELTA$deltatemp, 12) > > What does this mean? Can you explain me please why I can not make this > simple calculation? And what can I do to the calculation? > > further information: > mode(DELTA) > [1] "list" > > DELTA$delta > ..... > [685] 6.04 7.84 8.01 8.43 6.6 6.33 8.42 8.86 10.25 8.2 9.32 9.77 > [697] 7.9 6.42 5.95 > 474 Levels: -0.02 -0.13 -0.22 -0.46 -0.55 -1.26 -1.83 -1.86 -2.45 -3.2 ... > 9.9 > What does this last row mean? Several things. 1) DELTA is not a data frame here. It is a list: mode(DELTA) 2) DELTA$delta is not a vector. It is a factor. For some reason when you generated DELTA, your delta has become a factor. Arithematic operations on factors are meaningless. HTH. Kevin -------------------------------------------- Ko-Kang Kevin Wang, MSc(Hon) Statistics Workshops Co-ordinator Student Learning Centre University of Auckland New Zealand ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html