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]]
Hi,
The + is a special character in regular expressions. If you want to
match a literal + you need to escape it:
str_extract("+proj=utm +zone=19 +datum=WGS84 +units=m +no_defs
+ellps=WGS84 +towgs84=0,0,0", "\\+proj=[a-zA-Z0-9]*")
Sarah
On Thu, Aug 13, 2015 at 2:55 PM, 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
>
thanks.... that makes sense... in the previous version of R it worked for some reason. On Thu, Aug 13, 2015 at 4:33 PM, Sarah Goslee <sarah.goslee at gmail.com> wrote:> Hi, > > The + is a special character in regular expressions. If you want to > match a literal + you need to escape it: > > str_extract("+proj=utm +zone=19 +datum=WGS84 +units=m +no_defs > +ellps=WGS84 +towgs84=0,0,0", "\\+proj=[a-zA-Z0-9]*") > > Sarah > > > On Thu, Aug 13, 2015 at 2:55 PM, 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]]
"+" 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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