False AttributeError.

[Ismael-VC]

I was trying to answer this question at StackOverflow:

• http://stackoverflow.com/questions/31261350/automatically-generate-ijulia-notebooks

So I try to use PyCall:

• http://nbviewer.ipython.org/gist/Ismael-VC/4c4fcee41b8761af9673

And I get this error at Out [7]:

PyError (:PyObject_Call) <type 'exceptions.AttributeError'>
AttributeError("'dict' object has no attribute 'worksheets'",)
  File "/usr/local/lib/python2.7/dist-packages/IPython/nbformat/current.py", line 188, in write
    s = writes(nb, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/IPython/nbformat/current.py", line 154, in writes
    return versions[version].writes_json(nb, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/IPython/nbformat/v3/nbjson.py", line 48, in writes
    nb = split_lines(nb)
  File "/usr/local/lib/python2.7/dist-packages/IPython/nbformat/v3/rwbase.py", line 85, in split_lines
    for ws in nb.worksheets:

while loading In[7], in expression starting on line 3

 in pyerr_check at /home/juser/.julia/v0.3/PyCall/src/exception.jl:58
 in pycall at /home/juser/.julia/v0.3/PyCall/src/PyCall.jl:91
 in fn at /home/juser/.julia/v0.3/PyCall/src/conversions.jl:188
 in anonymous at In[7]:4
 in open at iostream.jl:137

But the dictionary in question indeed does have a worksheets key, as can be seen at Out [8].

[stevengj]

The dict has an "worksheets" key, but not a worksheets attribute.

I think the problem here may be that the conversion to a Julia Dict is losing some Python info. Try using lower-level functions that give you more control over the type conversions:

nbf = pyimport("IPython.nbformat.current")
nb = pycall(nbf["new_notebook"], PyDict)

or even nb = pycall(nbf["new_notebook"], PyObject)

[Ismael-VC]

@stevengj I did what you told me, but now in this part:

fname = "test.ipynb"

open(fname, "w") do f
    nbf[:write](nb, f, "ipynb")
end

I have this error:

PyError (:PyObject_Call) <type 'exceptions.TypeError'>
TypeError("'unicode' does not have the buffer interface",)
  File "/usr/local/lib/python2.7/dist-packages/IPython/nbformat/current.py", line 191, in write
    return fp.write(s)

while loading In[6], in expression starting on line 3

 in pyerr_check at /home/juser/.julia/v0.3/PyCall/src/exception.jl:58
 in pycall at /home/juser/.julia/v0.3/PyCall/src/PyCall.jl:91
 in fn at /home/juser/.julia/v0.3/PyCall/src/conversions.jl:188
 in anonymous at In[6]:4
 in open at iostream.jl:137

I don't know hot to convert an ASCIIString into a normal Python string (not unicode). I tried aliasing python with python3 and also this:

function PyCall.PyObject(s::ASCIIString)
    PyCall.@pyinitialize
    PyObject(PyCall.@pycheckn ccall(pystring_fromstring,
                                 PyPtr, (Ptr{Uint8},), bytestring(s)))
end

but then I get:

PyObject(ascii("test"))

s not defined
while loading In[15], in expression starting on line 1

 in PyObject at In[12]:88

I haven't been able to figure out why.

[yuyichao]

@Ismael-VC I checked the python source and AFAICT the issue is not passing a bytestring to python, rather python is passing a string (unicode) to julia and julia don't know how to write it to the file object.

My working example here

Also note that the interface is deprecated (You can see the deprecation warning from a ipython notebook) and AFAICT it is encouraged to specify the version of the notebook format directly.

[yuyichao]

Also, to convert a python str to bytes you can do what you would do in python, i.e. calling encode on it.

[stevengj]

See also http://stackoverflow.com/questions/25115042/typeerror-unicode-does-not-have-the-buffer-interface