[R] more structure than 'str'?
spencer.graves at pdf.com
Mon Dec 17 03:44:53 CET 2007
How can I see more of the structure than displayed by 'str'?
Consider the following:
tstDF <- data.frame(a=1, row.names='b')
'data.frame': 1 obs. of 1 variable:
$ a: num 1
The object 'tstDF' has row.names, but I have to suspect they are
there -- AND know a function like 'row.names' or 'dimnames' -- to see
I've found 'str' extremely valuable for understanding and
explaining to others the internal structure of an R object. In many
cases, it has helped me find fairly simple ways to do things with R
objects that might have been much more difficult and perhaps infeasible
without 'str' -- and without access to the right expert, who may not be
available in the time I have to solve a particular problem.
Thanks again to Martin Maechler, who wrote 'str', and to everyone
else who has replied to questions from me over the years.
p.s. 'methods(class="data.frame")' would help in this example.
However, 'methods' won't always find all available and recommended
extractor functions. For example, 'methods(class="lm")' was not able to
find 'AIC' for me just now.
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