[R] documentation / An Intro to R / list manipulation

Robbie Morrison robbie at actrix.co.nz
Thu Jun 4 19:02:23 CEST 2009


Hello R users

  http://cran.r-project.org/doc/manuals/R-intro.html
  An Introduction to R
  6.2 Constructing and modifying lists

After a short but successful struggle with nested
associative arrays (using named lists), I think the
following documentation change might be beneficial.

The existing description and example (see below)
implies that the given statement would transfer the
component name as well (not so):

    > Lst[5] <- list(matrix=Mat)

---------------------------------
 new text for section 6.2
---------------------------------

Lists, like any subscripted object, can be extended by
specifying additional components. For example

    > Lst[5] <- list(Mat)

This new component can also be named, using either a
character string (as shown) or suitable string variable

    > names(Lst)[5] <- "matrix"

---------------------------------
 test code
---------------------------------

  Mat <- matrix()
  Lst <- list()
  Lst[1] <- list(matrix = Mat)
  str(Lst)
  # List of 1
  #  $ : logi [1, 1] NA
  names(Lst)[1] <- "matrix"
  str(Lst)
  # List of 1
  #  $ matrix: logi [1, 1] NA


many thanks to the R team in general
Robbie

ps: I'm using R for visualizing data, including
directed graphs (via adjacency lists) and timeseries,
and for summarizing relatively diverse but consistent
datasets
---
Robbie Morrison
PhD student -- policy-oriented energy system simulation
Technical University of Berlin (TU-Berlin), Germany
University email (redirected) : morrison at iet.tu-berlin.de
Webmail (preferred)           : robbie at actrix.co.nz
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