[R] Regexpr with "."

John Zhang jzhang at jimmy.harvard.edu
Wed Aug 13 17:01:51 CEST 2003


regexpr("\\.", "Female.Alabama") and gsub("\\.", ",", "Female.Alabama")

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>Date: Wed, 13 Aug 2003 10:46:45 -0400
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>I'm trying to use the regexpr function to locate the decimal in a character
>string.  Regardless of the position of the decimal, the function returns 1.
>For example,
>> regexpr(".", "Female.Alabama")
>[1] 1
>[1] 1
>In trying to figure out what was going on here, I tried the below command:
>> gsub(".", ",", "Female.Alabama")
>[1] ",,,,,,,,,,,,,,"
>It looks like R is treating every character in the string as if it were
>decimal.  I didn't see anything in the help file about "." being some kind
>of special character.  Any idea why R is treating a decimal this way in
>these functions?   Any suggestions how to get around this?
>Thanks for any suggestions.
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Jianhua Zhang
Department of Biostatistics
Dana-Farber Cancer Institute
44 Binney Street
Boston, MA 02115-6084

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