[R] stringr package question

[Jeff Newmiller]

"+" is a special character in regular expressions that requires a preceding pattern to apply to. See ?base::regex.
You need to escape the special with a backslash to remove the special behavior, and escape the backslash so the R parser will be happy.

str_extract("+proj=utm +zone=19 +datum=WGS84 +units=m +no_defs +ellps=WGS84 +towgs84=0,0,0", "\\+proj=[a-zA-Z0-9]*")

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On August 13, 2015 11:55:36 AM PDT, Mauricio Romero <mauricioromerolondono at gmail.com> wrote:
>Hi,
>
>I'm running R 3.2.1 and im having an unexpected problem... when I run
>the
>follwing code it returns an error
>
>library(stringr)
>str_extract("+proj=utm +zone=19 +datum=WGS84 +units=m +no_defs
>+ellps=WGS84
>+towgs84=0,0,0", "+proj=[a-zA-Z0-9]*")
>
>But I can't find whats wrong with my code.
>
>Thanks
>
>Mauricio
>
>	[[alternative HTML version deleted]]
>
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