Yup you're right, after posting i took a better look at the subsetting, found the problem and post again, my bad...
2009/10/27 Duncan Murdoch <murd...@stats.uwo.ca>: > On 27/10/2009 2:58 PM, marcos carvajalino wrote: >> >> Dear ms. >> >> The most possible reason for this: >> >>> Dear all >>> I am trying to learn R >>> I was trying to calculate standard deviation >>> here are the commands and outputs in R >>>> >>>> sd(Ht_cm[type=='SD'])[1] 3.283605> sd(Ht_cm[from_treeline=='above'])[1] >>>> 16.83289> >sd(Ht_cm[type=='SD'][from_treeline=='above'])[1] NA> >> >>> the problem is that, i could not understand why the third command could >>> not give any >result. >> >>> please help me out >> >>> thanking you >> >>> Regard >>> MS >>> Nepal >> >> is that you're trying to calculate sd over a vector where a NA (Not >> available) value is contained, that is, you have an empty cell, a >> different type of data or no data satisfies your condition, try: >> >>> sd(Ht_cm[type=='SD'][from_treeline=='above'],na.rm=T) >> >> That should do it... > > That's legal syntax, but it is very unlikely to be correct. Hadley gave > good advice (modulo his typo). > > Duncan Murdoch > -- Marcos Antonio Carvajalino Fernández Estudiante de Ingeniería Ambiental y Sanitaria Universidad del Magdalena, Colombia ______________________________________________ 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.
