Message-ID: <4B491F20.3040504@ucdavis.edu>
Date: 2010-01-10T00:28:16Z
From: Greg Hirson
Subject: string functions
In-Reply-To: <82FE69CD-42A4-4C26-9F14-A8ABEDC64388@gmx.ch>
Laetitia,
One approach:
lettermatch <- function(stringA, stringB) {
sum(unique(unlist(strsplit(stringA, ""))) %in%
unique(unlist(strsplit(stringB, ""))))
}
lettermatch("Hello World","Hello Peter")
yields 6, as the l is only singly counted.
This treats uppercase and lowercase as different letters and counts how
many of the unique letters in stringA show up in stringB.
In another approach, letters are set to lowercase first. This I think
gives you what you want:
lettermatch2 <- function(stringA, stringB) {
tb <- merge(as.data.frame(table(strsplit(tolower(stringA), ""))),
as.data.frame(table(strsplit(tolower(stringB), ""))), by="Var1")
sum(apply(tb[-1], 1, min))
}
lettermatch("Hello World","Hello Peter")
yields 7.
Greg
On 1/9/10 1:51 PM, Laetitia Schmid wrote:
> Hi!
> Does anybody know a string function that would calculate how many
> characters two strings share? I.e. ("Hello World","Hello Peter") would
> be 7.
> Thanks.
> Laetitia
>
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--
Greg Hirson
ghirson at ucdavis.edu
Graduate Student
Agricultural and Environmental Chemistry
1106 Robert Mondavi Institute North
One Shields Avenue
Davis, CA 95616