From: Duncan Murdoch <murdoch_at_stats.uwo.ca>

Date: Sun 14 May 2006 - 08:04:08 EST

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Sun May 14 08:10:35 2006

Date: Sun 14 May 2006 - 08:04:08 EST

On 5/13/2006 2:52 PM, Ben Fairbank wrote:

> I have several data frames, each with six variables and several hundred

*> cases broken out from a larger dataframe by eleven values of a factor
**> called "Division". I have to perform the same analysis on each one. I
**> would like to do it by creating a data frame called data2 eleven times,
**> once with data corresponding to each value of the factor, and performing
**> the same analysis on each of the eleven values of data2. However, when
**> I assign to data2 the value of one of my data frames, e.g. data2 <-
**> Florida, and then attach data2, I get the warning
**>
**>
**>
**> The following object(s) are masked from data2 ( position 3 ) :
**>
**> Day Division SchedNo Spent TimeEnter TimeInStr
**>
**> The following object(s) are masked from Alb3 :
**>
**> Day Division SchedNo Spent TimeEnter TimeInStr
**>
**> The following object(s) are masked from data2 ( position 5 ) :
**>
**> Day Division SchedNo Spent TimeEnter TimeInStr
**>
**>
**>
**> I am having trouble finding an explanation of these messages, what the
**> "position" refers to, and what it means to be "masked." Can someone
**> steer me to an online explanation?
*

It is the position in the search list. See search() for the complete list.

It sounds as though you are attaching things, but not detaching them: and R is warning that the new attach is hiding something from the previous one.

The Introduction to R manual discusses this in the "Data frames" section of the "Lists and data frames" chapter.

Duncan Murdoch

*>
**>
**>
*

> And by the way, one of the analyses I have to perform is simply to

*> tabulate the days of the week that occur in variable "Day" by using
**> table(Day) which gives, for example,
**>
**>
**>
**> Day
**>
**> Fri Mon Sat Sun Thur Tue Wed
**>
**> 173 191 111 92 188 218 187
**>
**>
**>
**> What is the proper syntax for doing that by levels of a factor within
**> the large data frame containing all eleven factors? I have
**> unsuccessfully tried to use "by".
**>
**>
**>
**> Thanks,
**>
**>
**>
**> Ben F.
**>
**>
**> [[alternative HTML version deleted]]
**>
**> ______________________________________________
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**> https://stat.ethz.ch/mailman/listinfo/r-help
**> PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
*

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