Message-ID: <33ee61ee-9d45-3a14-5eb0-107b1dc37653@rgzm.de>
Date: 2020-08-20T06:38:04Z
From: Ivan Calandra
Subject: & and |
In-Reply-To: <CABcYAdJo6GskigEuAx+LRkQY87wk8bDL7OL2i2dx3xrXL4vDEQ@mail.gmail.com>
Thank you all for all the very helpful answers!
Best,
Ivan
--
Dr. Ivan Calandra
TraCEr, laboratory for Traceology and Controlled Experiments
MONREPOS Archaeological Research Centre and
Museum for Human Behavioural Evolution
Schloss Monrepos
56567 Neuwied, Germany
+49 (0) 2631 9772-243
https://www.researchgate.net/profile/Ivan_Calandra
On 20/08/2020 3:28, Richard O'Keefe wrote:
> There are & and | operators in the R language.
> There is an | operator in regular expressions.
> There is NOT any & operator in regular expressions.
> grep("ConfoMap&GuineaPigs", mydata, value=TRUE)
> looks for elements of mydata containing the literal
> string 'ConfoMap&GuineaPigs'.
>
> > foo <- c("a","b","cab","back")
> > foo[grepl("a",foo) & grepl("b",foo)]
> [1] "cab" ?"back"
>
> grepl returns a TRUE/FALSE vector.
>
> On Thu, 20 Aug 2020 at 02:53, Ivan Calandra <calandra at rgzm.de
> <mailto:calandra at rgzm.de>> wrote:
>
> Dear useRs,
>
> I feel really stupid, but I cannot understand why "&" doesn't work
> as I
> expect, while "|" does.
>
> I have the following vector:
> mydata <- c("SSFA-ConfoMap_GuineaPigs_NMPfilled.csv",
> "SSFA-ConfoMap_Lithics_NMPfilled.csv",?
> "SSFA-ConfoMap_Sheeps_NMPfilled.csv",
> "SSFA-Toothfrax_GuineaPigs.xlsx",
> "SSFA-Toothfrax_Lithics.xlsx", "SSFA-Toothfrax_Sheeps.xlsx")
> and I want to find the values that include both "ConfoMap" and
> "GuineaPigs".
>
> If I do:
> grep("ConfoMap&GuineaPigs", mydata, value=TRUE)
> it returns an empty vector, character(0).
>
> But if I do:
> grep("ConfoMap|GuineaPigs", mydata, value=TRUE)
> it returns all the elements that include either "ConfoMap" or
> "GuineaPigs", as I would expect.
>
> So what is wrong with my "&" construct? How can I return the elements
> that include both parts?
>
> Thank you for your help!
> Ivan
>
> --
> Dr. Ivan Calandra
> TraCEr, laboratory for Traceology and Controlled Experiments
> MONREPOS Archaeological Research Centre and
> Museum for Human Behavioural Evolution
> Schloss Monrepos
> 56567 Neuwied, Germany
> +49 (0) 2631 9772-243
> https://www.researchgate.net/profile/Ivan_Calandra
>
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