On Nov 2, 2012, at 11:20 AM, VictorDelgado wrote:
> Hello dear R-helpers,
>
> I'm working with R-2.15.2 on Windows 7 OS. I'm stucked with a merge of two
> data frames by characters.
> In each data frame I got two different list of names, that is my main-key to
> be merged.
>
> To figure out what I'm saying, I build up a modified "?merge" example, with
> errors by purpose:
>
> # Data for authors:
>
> authors <- data.frame(
> surname = I(c("Tukey", "Venable", "Terney", "Ripley", "McNeil")),
> nationality = c("US", "Australia", "US", "UK", "Australia"),
> deceased = c("yes", rep("no", 4)))
>
> "Venables" is without the final 's', and "Tierney, without "i".
>
> # Data for books:
>
> books <- data.frame(
> surname = I(c("Tukey", "Venables", "Tierney",
> "Ripley", "Rippley", "McNeil", "R Core")),
> title = c("Exploratory Data Analysis",
> "Modern Applied Statistics ...",
> "LISP-STAT",
> "Spatial Statistics", "Stochastic Simulation",
> "Interactive Data Analysis",
> "An Introduction to R"),
> other.author = c(NA, "Ripley", NA, NA, NA, NA,
> "Venables & Smith"))
In your example the authors list has better spelling. The 'agrep' functions by
default will return matches that are 90% ( or more precisely Levenshtein
distance of less than or equalt to 0.1) :
books$altname <- NA
altidx <- unlist( sapply(books$surname, agrep, authors$surname) )
books$altname[seq(altidx)] <- authors$surname[altidx]
books
#-----------------------
surname title other.author altname
1 Tukey Exploratory Data Analysis <NA> Tukey
2 Venables Modern Applied Statistics ... Ripley Venable
3 Tierney LISP-STAT <NA> Terney
4 Ripley Spatial Statistics <NA> Ripley
5 Rippley Stochastic Simulation <NA> Ripley
6 McNeil Interactive Data Analysis <NA> McNeil
7 R Core An Introduction to R Venables & Smith <NA>
If you then match 'books' to 'authors' with a merge on authors$surname and
books$altname, you should get closer to your goals
--
David.
>
> With "surname" column instead of "name" (differs from original example for
> more easy going merge). And the second "Ripley" with double "p".
>
> So, if I ask for:
>
> merge(authors, books, all=TRUE)
>
> I got:
>
>
> But we know that "Rippley" corresponds to "Ripley", "Terney" to "Tierney"
> and "Venable" to "Venables". I was wondering if there was any way to work
> around this problem. My orginal data have around 27,000 name entries, and if
> I take "all=FALSE", this database drops out to around 17,000, most because
> mispelling (or truncated expressions). If I take "all=TRUE", I got many of
> this <NA> cases like the example above.
>
> Has anyone experienced this? Any idea how I can get out? I'm thinking to
> take the longest match possible to each entry. For example, in
> "Venable"/"Venables" there is a 87.5% match. As I have name and surname, and
> also auxiliary keys to this match, I think this could work.
>
> Thank you in advance.
>
>
>
> -----
> Victor Delgado
> cedeplar.ufmg.br P.H.D. student
> www.fjp.mg.gov.br reseacher
> --
> View this message in context:
> http://r.789695.n4.nabble.com/Merge-data-frame-with-mispelling-characters-tp4648255.html
> Sent from the R help mailing list archive at Nabble.com.
>
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
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David Winsemius, MD
Alameda, CA, USA
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