[R] Merge data frame with mispelling characters

[VictorDelgado]

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"))
 
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
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