ctable.fromdataframe() does not support named columns

[dirkbike]

Not sure if this is a bug, but it seems that fromdataframe should be able to support the following use case:

In [1]: import pandas as pd

In [2]: from pandas_datareader import data as web

In [3]: import bcolz as bz

In [4]: pd.__version__
Out[4]: '0.18.1'

In [5]: bz.__version__
Out[5]: '1.1.0'

In [6]: pd.options.display.width = 120

In [7]: df = web.get_data_yahoo('^gspc', '1960-01-01', '2016-01-01')

In [8]: df.head()
Out[8]:
                 Open       High        Low      Close   Volume  Adj Close
Date
1960-01-04  59.910000  59.910000  59.910000  59.910000  3990000  59.910000
1960-01-05  60.389999  60.389999  60.389999  60.389999  3710000  60.389999
1960-01-06  60.130001  60.130001  60.130001  60.130001  3730000  60.130001
1960-01-07  59.689999  59.689999  59.689999  59.689999  3310000  59.689999
1960-01-08  59.500000  59.500000  59.500000  59.500000  3290000  59.500000

In [9]: dfz = bz.ctable.fromdataframe(df, rootdir='gspc.bz')
---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-9-a5ef4f82fc21> in <module>()
----> 1 dfz = bz.ctable.fromdataframe(df, rootdir='gspc.bz')

C:\Python34\lib\site-packages\bcolz\ctable.py in fromdataframe(df, **kwargs)
    694
    695         # Create the ctable
--> 696         ct = ctable(cols, names, **kwargs)
    697         return ct
    698

C:\Python34\lib\site-packages\bcolz\ctable.py in __init__(self, columns, names, **kwargs)
    253             self._open_ctable()
    254         elif columns is not None:
--> 255             self._create_ctable(columns, names, **kwargs)
    256             _new = True
    257         else:

C:\Python34\lib\site-packages\bcolz\ctable.py in _create_ctable(self, columns, names, **kwargs)
    289                     "`columns` and `names` must have the same length")
    290         # Check names validity. Cast to string.
--> 291         names = validate_names(names)
    292
    293         # Guess the kind of columns input

C:\Python34\lib\site-packages\bcolz\ctable.py in validate_names(columns, keyword)
     33 def validate_names(columns, keyword='names'):
     34     if not all([is_identifier(x) and not iskeyword(x) for x in columns]):
---> 35         raise ValueError("{0} are not valid idenifiers".format(keyword))
     36     return list(map(str, columns))
     37

ValueError: names are not valid idenifiers

Also, note that the error message misspelled the word "identifiers."

[ankravch]

Column names should not contain whitespace characters like 'Adj Close'

This should work
df.columns = [''.join(icol.split()) for icol in df.columns.values.tolist()]
dfz = bz.ctable.fromdataframe(df, rootdir='gspc.bz')

On Fri, Aug 19, 2016 at 8:58 AM, dirkbike notifications@github.com wrote:

Not sure if this is a bug, but it seems that fromdataframe should be able
to support the following use case:

In [1]: import pandas as pd

In [2]: from pandas_datareader import data as web

In [3]: import bcolz as bz

In [4]: pd.version
Out[4]: '0.18.1'

In [5]: bz.version
Out[5]: '1.1.0'

In [6]: pd.options.display.width = 120

In [7]: df = web.get_data_yahoo('^gspc', '1960-01-01', '2016-01-01')

In [8]: df.head()
Out[8]:
Open High Low Close Volume Adj Close
Date
1960-01-04 59.910000 59.910000 59.910000 59.910000 3990000 59.910000
1960-01-05 60.389999 60.389999 60.389999 60.389999 3710000 60.389999
1960-01-06 60.130001 60.130001 60.130001 60.130001 3730000 60.130001
1960-01-07 59.689999 59.689999 59.689999 59.689999 3310000 59.689999
1960-01-08 59.500000 59.500000 59.500000 59.500000 3290000 59.500000

In [9]: dfz = bz.ctable.fromdataframe(df, rootdir='gspc.bz')

ValueError Traceback (most recent call last)
in ()
----> 1 dfz = bz.ctable.fromdataframe(df, rootdir='gspc.bz')

C:\Python34\lib\site-packages\bcolz\ctable.py in fromdataframe(df, *_kwargs)
694
695 # Create the ctable
--> 696 ct = ctable(cols, names, *_kwargs)
697 return ct
698

C:\Python34\lib\site-packages\bcolz\ctable.py in init(self, columns, names, *_kwargs)
253 self._open_ctable()
254 elif columns is not None:
--> 255 self._create_ctable(columns, names, *_kwargs)
256 _new = True
257 else:

C:\Python34\lib\site-packages\bcolz\ctable.py in _create_ctable(self, columns, names, **kwargs)
289 "columns and names must have the same length")
290 # Check names validity. Cast to string.
--> 291 names = validate_names(names)
292
293 # Guess the kind of columns input

C:\Python34\lib\site-packages\bcolz\ctable.py in validate_names(columns, keyword)
33 def validate_names(columns, keyword='names'):
34 if not all([is_identifier(x) and not iskeyword(x) for x in columns]):
---> 35 raise ValueError("{0} are not valid idenifiers".format(keyword))
36 return list(map(str, columns))
37

ValueError: names are not valid idenifiers

Also, note that the error message misspelled the word "identifiers."

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[dirkbike]

Thanks, that does work. I recommend changing the error message from "names are not valid idenifiers" to "column names must be valid Python identifiers." That will make the error a lot more obvious.

[FrancescAlted]

@dirkbike Yes, I think your suggestion is better. Could you please provide a PR?

[dirkbike]

see #315

[FrancescAlted]

Fixed in #315