On 7/21/10 9:39 PM, rey sebastien wrote:
> On 21/07/2010 18:27, Laurent wrote:
>> On 21/07/10 16:54, rey sebastien wrote:
>>> Hello guys,
>>> I'm having some trouble to understand the mapping with rpy2 object and
>>> python object.
>>>
>>> I have a function(x) which return a tuple object in python, and i want
>>> to map this tuple object with R object list or vector.
>>> _
>>> First, i'm trying to do this : _
>>>
>>> robjects.r.tlist = get_max_ticks(x) # return a tuple into this object
>>> tlist
>>>
>>> #Convert list into dataframe
>>> r('x <- as.data.frame(tlist,row.names=c("seed","ticks"))')
>>>
>>> FAIL with error :
>>> rinterface.RRuntimeError: Error in eval(expr, envir, enclos) : object
>>> 'tlist' not found
>>> _
>>> So i'm trying an other strategy : _
>>>
>>> robjects.r["tlist"] = get_max_ticks(x)
>>> r('x <- as.data.frame(tlist,row.names=c("seed","ticks"))')
>>>
>>>
>>> FAIL with this error :
>>> TypeError: 'R' object does not support item assignment
>>>
>>> Could you help me to understand ?
>>
>>
>> What about starting with the documentation ?
>>
>> http://rpy.sourceforge.net/rpy2/doc-2.1/html/robjects.html#creating-objects
>>
>>
>>
>>
> Thx but i have already read a part of the official documentation, but it
> seems this paragraph don't resolve my problem :/
You may still want to consider spending a little more time on the
introduction, as you might continue struggling much otherwise.
> A guys on stackoverflow resolve my problem, and explain this :*
The code below only works on an older version of rpy2. I'd go for the
most recent version as much I could.
> import rpy2.robjects as ro
> r=ro.r
>
> def get_max_ticks():
> return (1,2)
> ro.globalEnv['tlist'] = ro.FloatVector(get_max_ticks())
> r('x <- as.data.frame(tlist,row.names=c("seed","ticks"))')
> print(r['x'])
> # tlist
> # seed 1
> # ticks 2
>
>
> It may be possible to access symbols in the R namespace with this type
Explained in the "introduction":
http://rpy.sourceforge.net/rpy2/doc-2.1/html/introduction.html#getting-r-objects
> of notation: robjects.r.tlist, but you can not assign values this way.
> The way to assign symbol is to use robject.globalEnv.
The link given above has link to the URL below:
http://rpy.sourceforge.net/rpy2/doc-2.1/html/robjects.html#robjects-environments
This tells about globalenv. It also tells that assigning to globalenv
should be considered with care.
> Moreover, some symbols in R may contain a period, such as data.frame.
> You can not access such symbols in Python using notation similar to
> robjects.r.data.frame, since Python interprets the period differently
> than R.
The last link given above is pointing to the use of packages, where a
dot-to-underscore translation is performed:
http://rpy.sourceforge.net/rpy2/doc-2.1/html/robjects.html#robjects-packages
The section on functions is also talking about dots and underscores:
http://rpy.sourceforge.net/rpy2/doc-2.1/html/robjects.html?highlight=dataframe#functions
> So I'd suggest avoiding this notation entirely, and instead use
> robjects.r['data.frame'], since this notation works no matter what the
> symbol name is.*
I'd suggest investing time in learning about the class
rpy2.robjects.DataFrame(), really.
> the link for answer :
> http://stackoverflow.com/questions/3300671/mapping-python-tuple-and-r-list-with-rpy2
>
> Thx a lot!
> S.Rey
>
>>
>>
>>
>>
>>> Thanks a lot !!
>>>
>>> ------
>>> S.Rey
>>> Phd @ "geographie-cités" Paris
>>>
>>>
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