Re: std::vector<Bool_t> in PyROOT

From: OKUMURA, Akira <oxon_at_astro.isas.jaxa.jp>
Date: Mon, 28 Jun 2010 21:37:14 -0700

Hello Wim,

Here is the result of dir().

>>> dir(test.b)
['__add__', '__assign__', '__class__', '__delattr__', '__dict__', '__div__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__gt__', '__hash__', '__init__', '__le__', '__len__', '__lt__', '__module__', '__mul__', '__ne__', '__new__', '__nonzero__', '__radd__', '__rdiv__', '__reduce__', '__reduce_ex__', '__repr__', '__rmul__', '__rsub__', '__setattr__', '__sizeof__', '__str__', '__sub__', '__subclasshook__', '__weakref__', 'assign', 'begin', 'capacity', 'clear', 'empty', 'end', 'erase', 'insert', 'max_size', 'pop_back', 'push_back', 'rbegin', 'rend', 'reserve', 'resize', 'size', 'swap', 'vector'] >>> dir(test.d)
['__add__', '__assign__', '__class__', '__delattr__', '__dict__', '__div__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__gt__', '__hash__', '__init__', '__le__', '__len__', '__lt__', '__module__', '__mul__', '__ne__', '__new__', '__nonzero__', '__radd__', '__rdiv__', '__reduce__', '__reduce_ex__', '__repr__', '__rmul__', '__rsub__', '__setattr__', '__setitem__', '__sizeof__', '__str__', '__sub__', '__subclasshook__', '__weakref__', '_vector__at', 'at', 'back', 'begin', 'capacity', 'clear', 'empty', 'end', 'erase', 'front', 'insert', 'max_size', 'pop_back', 'push_back', 'rbegin', 'rend', 'reserve', 'resize', 'size', 'swap', 'vector']

As you can see above, a part of vector's method can be accessed from python. For example, test.b.size() returns 3L as expected.

'__getitem__', '__setitem__', '_vector__at', 'at', 'back', 'front' are missing in vector<Bool_t> but it has 'assign' method instead.

I found that this is not a limitation by PyROOT but CINT itself has this problem. Below is the minimum code to produce this.

root [0] #include <vector>
root [1] std::vector<Bool_t> v(3, 0)
root [2] v[0]

Error: Can't call vector<bool,allocator<bool> >::operator[]((int)0) in current scope (tmpfile):1: Possible candidates are...
(in vector<bool,allocator<bool> >)
*** Interpreter error recovered ***

I get the same result on both OS X 10.6 and Scientific Linux 5 with ROOT 5.27.02.

Regards,

--
OKUMURA, Akira oxon@{astro.isas.jaxa.jp,stanford.edu}
Institute of Space and Astronautical Science (ISAS/JAXA)
Now at KIPAC/SLAC/Stanford
Varian Physics #306
382 Via Pueblo Mall, MC 406 Stanford, CA94305
TEL 650-736-0971/FAX 650-724-5065
Skype : okumura.akira

On 2010/06/28, at 21:11, WLavrijsen_at_lbl.gov wrote:



> Akira,

> 

>> File "test.py", line 27, in <module>
>>  print b[i]
>> TypeError: 'vector<bool,allocator<bool> >' object does not support indexing


> 

> typically means that there's no dictionary loaded for said vector class. Have

> a look at the results of dir(b) and see whether it has the normal methods.

> 

> Best regards,

>          Wim

> -- 

> WLavrijsen_at_lbl.gov    --    +1 (510) 486 6411    --    www.lavrijsen.net

Received on Tue Jun 29 2010 - 06:37:46 CEST