Pandas read_csv dtype=str fails on empty csv file

[matthew....@performgroup.com]

Hi,

I have a csv file that is generated daily. It contains a combination of fields that, for arguments sake, I want to treat as strings. I do this like so:

df = pd.read_csv(f, dtype=str)

This works great when the csv file has rows. However, when the daily csv file is empty (which can happen) Pandas throws an exception:

Traceback (most recent call last):

  File "<stdin>", line 1, in <module>

  File "/usr/local/lib/python2.7/site-packages/pandas/io/parsers.py", line 498, in parser_f

    return _read(filepath_or_buffer, kwds)

  File "/usr/local/lib/python2.7/site-packages/pandas/io/parsers.py", line 285, in _read

    return parser.read()

  File "/usr/local/lib/python2.7/site-packages/pandas/io/parsers.py", line 747, in read

    ret = self._engine.read(nrows)

  File "/usr/local/lib/python2.7/site-packages/pandas/io/parsers.py", line 1204, in read

    dtype=self.kwds.get('dtype'))

  File "/usr/local/lib/python2.7/site-packages/pandas/io/parsers.py", line 2259, in _get_empty_meta

    for k, v in compat.iteritems(dtype))

  File "/usr/local/lib/python2.7/site-packages/pandas/compat/__init__.py", line 134, in iteritems

    func = obj.items

AttributeError: type object 'str' has no attribute 'items'

You can easily replicate this:

import pandas as pd
from StringIO import StringIO

csv = StringIO('col1,col2,col3')
df = pd.read_csv(csv, dtype=str)

I notice that if I pass a dict into dtype it actually works fine:

import pandas as pd
from StringIO import StringIO

csv = StringIO('col1,col2,col3')
df = pd.read_csv(csv, dtype={'col1': str})

Is this a known issue? Or is it something silly I'm doing?

Any thoughts would be appreciated as it would be much simpler for me to treat all columns as strings, rather than identifying specific ones.

Thanks.

Just in case this is of use:

INSTALLED VERSIONS

------------------

commit: None

python: 2.7.10.final.0

python-bits: 64

OS: Darwin

OS-release: 15.3.0

machine: x86_64

processor: i386

byteorder: little

LC_ALL: None

LANG: en_GB.UTF-8

pandas: 0.17.1

nose: 1.3.7

pip: 8.0.2

setuptools: 18.7.1

Cython: None

numpy: 1.10.1

scipy: None

statsmodels: None

IPython: None

sphinx: None

patsy: None

dateutil: 2.4.2

pytz: 2015.7

blosc: None

bottleneck: None

tables: None

numexpr: None

matplotlib: None

openpyxl: None

xlrd: None

xlwt: None

xlsxwriter: None

lxml: None

bs4: 4.4.1

html5lib: 0.9999999

httplib2: 0.9.2

apiclient: 1.4.2

sqlalchemy: 1.0.9

pymysql: None

psycopg2: 2.6.1 (dt dec pq3 ext lo64)

Jinja2: None