Better Message for xlrd Dependencies

[WillAyd]

Right now if you don't have xlrd installed and use read_excel without specifying the engine keyword you get the following message:

>>> pd.read_excel("test.xlsx")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/williamayd/.pyenv/versions/3.7.2/lib/python3.7/site-packages/pandas/util/_decorators.py", line 208, in wrapper
    return func(*args, **kwargs)
  File "/Users/williamayd/.pyenv/versions/3.7.2/lib/python3.7/site-packages/pandas/io/excel/_base.py", line 310, in read_excel
    io = ExcelFile(io, engine=engine)
  File "/Users/williamayd/.pyenv/versions/3.7.2/lib/python3.7/site-packages/pandas/io/excel/_base.py", line 819, in __init__
    self._reader = self._engines[engine](self._io)
  File "/Users/williamayd/.pyenv/versions/3.7.2/lib/python3.7/site-packages/pandas/io/excel/_xlrd.py", line 20, in __init__
    import_optional_dependency("xlrd", extra=err_msg)
  File "/Users/williamayd/.pyenv/versions/3.7.2/lib/python3.7/site-packages/pandas/compat/_optional.py", line 93, in import_optional_dependency
    raise ImportError(message.format(name=name, extra=extra)) from None
ImportError: Missing optional dependency 'xlrd'. Install xlrd >= 1.0.0 for Excel support Use pip or conda to install xlrd.

This is in spite of the fact that the user may have openpyxl installed and could do something like pd.read_excel(..., engine="openpyxl") to get the same code to work

Two issues need to be addressed here:

• The default read_excel call with no engine argument should fall back to openpyxl, if installed
• The default error message should direct the user to install openpyxl first and foremost, as xlrd is unmaintained

[codinggosu]

Can I work on this?

[WillAyd]

Sure!

[punndcoder28]

Can I work on this? I am new to contributing to issues on GitHub and this seems like a good start.

[punndcoder28]

I removed xlrd from versions and changed the default message to only include the pip install message like follows.

VERSIONS = {
"bs4": "4.6.0",
"bottleneck": "1.2.1",
"fastparquet": "0.2.1",
"gcsfs": "0.2.2",
"lxml.etree": "3.8.0",
"matplotlib": "2.2.2",
"numexpr": "2.6.2",
"odfpy": "1.3.0",
"openpyxl": "2.4.8",
"pandas_gbq": "0.8.0",
"pyarrow": "0.9.0",
"pytables": "3.4.2",
"s3fs": "0.0.8",
"scipy": "0.19.0",
"sqlalchemy": "1.1.4",
"tables": "3.4.2",
"xarray": "0.8.2",
"xlwt": "1.2.0",
"xlsxwriter": "0.9.8",
}
message = (
"Use pip or conda to install {name}."
)

Is what I am doing correct?

[codinggosu]

I changed the default engine to be openpyxl in pandas/io/excel/base to be openpyxl for the purpose of making the "default read_excel call with no engine argument" fall back to openpyxl.

Also I added an error message to pandas/io/excel/_openpyxl for the purpose of directing "the user to install openpyxl first and foremost,"

Am I heading in the right direction? Is this OK?

[WillAyd]

I changed the default engine to be openpyxl in pandas/io/excel/base to be openpyxl for the purpose of making the "default read_excel call with no engine argument" fall back to openpyxl

Don't want to make that change just yet - simply warn the user that the default will change in the future and they can explicitly say engine="openpyxl" to suppress or simply wait for the swap to be made in a future release

[codinggosu]

On it! thanks for the feedback

[tab1tha]

take

[SuvigyaJain1]

I'd like to work on this but this is my first time contributing to pandas as well as first time working with such a huge codebase. What general direction should i work in?