RPyGeo Query -- probably easy

Hi Alex,

Thank you so much for the suggestion and apologies for taking so long to test 
it. I think the quotes are still a problem. I do indeed write all my code in 
R-WinEdt but must be doing something wrong. In Python your suggested escaped 
quotes works fine but perhaps I missed something in RPyGeo:

This code works in Python:

gp.makefeaturelayer("abc.shp", "walk")
gp.SelectLayerByAttribute('walk','NEW_SELECTION','\"hrwk05\" <> 0')

This code works in R:

rpygeo.geoprocessor(
"makefeaturelayer('abc.shp', 'walk')",
"SelectLayerByAttribute('walk','NEW_SELECTION','')",
env=myenv)

This code gives me an error in R:

rpygeo.geoprocessor(
"makefeaturelayer('abc.shp','walk')",
"SelectLayerByAttribute('walk','NEW_SELECTION','\"hrwk05\" <> 0')",
env=myenv)

File "x:\projects\rpygeo.py", line 10
gp.makefeaturelayer('abc.shp','walk')( 
"SelectLayerByAttribute('walk','NEW_SELECTION','"hrwk05" <> 0')" )
                                                                                               ^
SyntaxError: invalid syntax
NULL

(note from Zev -- the carrot occurs under the "05")


Alexander Brenning wrote:

Hi Zev,

the problems are definitely your quotes. First, they are syntactically 
incorrect - I count seven double quotes (I recommend using some editor with 
syntax highlighting, like Tinn-R or R-WinEdt, this helps discover 
mismatches). Second, escaping them (\") should allow you to put double 
quotes inside a double-quoted character string.

This might be closer to what you want to do (but I haven't tried to run it 
- sorry, busy end of term...):

rpygeo.geoprocessor("makefeaturelayer('X:\\abc.shp','walk')",
    "SelectLayerByAttribute('walk','NEW_SELECTION','\"hrwk05\"<>0')",
    env=myenv)

Note that an additional argument clean.up=FALSE to the rpygeo.geoprocessor 
allows you to inspect the Python file to check whether the quotes are 
syntactically correct in Python.

I hope this helps
 Alex



Zev Ross wrote:

Hi All,

I'm wondering if anybody could give me a little guidance on formatting a 
query using RPyGeo. I'm excited to be able to run Python geoprocessing 
functions straight from R but am having trouble with the quote, double 
quote kinds of issues.

Here's an example of what I'd like to run

rpygeo.geoprocessor("makefeaturelayer('X:\\abc.shp',
'walk')", "SelectLayerByAttribute('walk','NEW_SELECTION', ' "hrwk05" 
'<>0")",env=myenv)

Where the sticking point is hrwk05 <> 0. In Python my query would be 
double quote, field name, close double quote, comparison, number e.g, 
"hrwk05" <> 0 but I'm not sure how to put this into RPyGeo

If I run like so:

rpygeo.geoprocessor("makefeaturelayer('X:\\abc.shp',
'walk')", "SelectLayerByAttribute('walk','NEW_SELECTION', '')",env=myenv)

it runs.

Thank you in advance for assistance.

Zev