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[BUGZILLA #10701] Suggestions for R-intro manual #3271

Open MichaelChirico opened 4 years ago

MichaelChirico commented 4 years ago

From: Tim Hesterberg <timh@<::CENSORED -- SEE ORIGINAL ON BUGZILLA::>> Some suggestions for R-intro:

-------------------------------------------------- Section 9.2.2, change: (Note the function split() which produces a list of vectors obtained by splitting a larger vector according to the classes specified by a factor. This is a useful function, mostly used in connection with boxplots. See the help facility for further details.)

Warning: for() loops are used in R code much less often than in
compiled languages. Code that takes a `whole object' view is
likely to be both clearer and faster in R.

to:

Warning: for() loops are used in R code much less often than in
compiled languages. Code that takes a `whole object' view is
likely to be both clearer and faster in R.

(Note the function split() which produces a list of vectors obtained by splitting a larger vector according to the classes specified by a factor. It can also split data frames. This is a useful function, often used in combination with lapply to avoid for() loops. See help(split) and help(lapply) for further details.)

-------------------------------------------------- Section 10.1

The current twosam is for a pooled-variance t-statistic. Give the unpooled version instead (for consistency with t.test, and because it is better statistical practice).

Give initial comments in functions twosam: # compute a two-sample t-statistic for the difference in means

and bslash: # Compute least-squares regression coefficients (X'X)^{-}(X'y)

Add initial comments to later functions; even if they are not needed, this sets a good example.

-------------------------------------------------- Section 11.1.1

This contains outdated information about contrasts in S-PLUS. For version 8.0.4:

options("contrasts")

$contrasts: factor ordered "contr.treatment" "contr.poly"

-------------------------------------------------- Section 11.3

In this text: predict(object, newdata=data.frame) The data frame supplied must have variables specified with the same labels as the original. The value is a vector or matrix of predicted values corresponding to the

it is unclear what "labels" means - same variable names, or same levels for factor variables. Change "variables specified with the same labels" to "variables with the same names".

-------------------------------------------------- Section 11.6

There is a newer version of Dobson, 2002, second edition.

Dobson is referenced later, in Section 11.7.2. I don't have the new copy, can't tell you new page numbers.

-------------------------------------------------- Section 12.1

Change "High-level plotting commands always start a new plot, erasing the current plot if necessary." to "High-level plotting commands start a new plot, erasing the current plot if necessary. This can be prevented using 'add=TRUE', see section 12.1.4" or "High-level plotting commands start a new plot, erasing the current plot if necessary."

-------------------------------------------------- Section 13.3

The last part of this sentence seems irrelevant to this section: Packages can have namespaces, and currently all of the base and recommended packages do expect the datasets package.

-------------------------------------------------- Appendix A

Preface comments with #. I'm looking at the web version of the manual, and there is nothing to distinguish continuations of long commands from comments. Using comments would also allow a user to paste a block of code into R.

--------------------------------------------------

Tim Hesterberg

--please do not edit the information below--

Version: platform = i386-pc-mingw32 arch = i386 os = mingw32 system = i386, mingw32 status = major = 2 minor = 6.1 year = 2007 month = 11 day = 26 svn rev = 43537 language = R version.string = R version 2.6.1 (2007-11-26)

Windows XP (build 2600) Service Pack 2.0

Locale: LC_COLLATE=English_United States.1252;LC_CTYPE=English_United States.1252;LC_MONETARY=English_United States.1252;LC_NUMERIC=C;LC_TIME=English_United States.1252

Search Path: .GlobalEnv, package:stats, package:graphics, package:grDevices, package:utils, package:datasets, package:methods, Autoloads, package:base

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MichaelChirico commented 4 years ago

Audit (from Jitterbug): Mon Apr 14 09:25:44 2008 ripley moved from incoming to Documentation

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