Leave dates as strings using read_excel function from pandas in python

Question

Python 2.7.10
Tried pandas 0.17.1 -- function read_excel
Tried pyexcel 0.1.7 + pyexcel-xlsx 0.0.7 -- function get_records()

When using pandas in Python is it possible to read excel files (formats: xls, xlsx) and leave columns containing date or date + time values as strings rather than auto-converting to datetime.datetime or timestamp types?

If this is not possible using pandas can someone suggest an alternate method/library to read xls, xlsx files and leave date column values as strings?

For the pandas solution attempts the df.info() and resulting date column types are shown below:

>>> df.info()
<class 'pandas.core.frame.DataFrame'>
Int64Index: 117 entries, 0 to 116
Columns: 176 entries, Mine to Index
dtypes: datetime64[ns](2), float64(145), int64(26), object(3)
memory usage: 161.8+ KB
>>> type(df['Start Date'][0])
Out[6]: pandas.tslib.Timestamp
>>> type(df['End Date'][0])
Out[7]: pandas.tslib.Timestamp

Attempt/Approach 1:

def read_as_dataframe(filename, ext):
   import pandas as pd
   if ext in ('xls', 'xlsx'):
      # problem: date columns auto converted to datetime.datetime or timestamp!
      df = pd.read_excel(filename) # unwanted - date columns converted!

   return df, name, ext

Attempt/Approach 2:

import pandas as pd
# import datetime as datetime
# parse_date = lambda x: datetime.strptime(x, '%Y%m%d %H')
parse_date = lambda x: x
elif ext in ('xls', 'xlsx', ):
    df = pd.read_excel(filename, parse_dates=False)
    date_cols = [df.columns.get_loc(c) for c in df.columns if c in ('Start Date', 'End Date')]
    # problem: date columns auto converted to datetime.datetime or timestamp!
    df = pd.read_excel(filename, parse_dates=date_cols, date_parser=parse_date)

And have also tried pyexcel library but it does the same auto-magic convert behavior:

Attempt/Approach 3:

import pyexcel as pe
import pyexcel.ext.xls
import pyexcel.ext.xlsx

t0 = time.time()
if ext == 'xlsx':
    records = pe.get_records(file_name=filename)
    for record in records:
        print("start date = %s (type=%s), end date = %s (type=%s)" %
              (record['Start Date'],
               str(type(record['Start Date'])),
               record['End Date'],
               str(type(record['End Date'])))
              )

Answer 1

I ran into an identical problem, except pandas was oddly converting only some cells into datetimes. I ended up manually converting each cell into a string like so:

def undate(x):
    if pd.isnull(x):
        return x
    try:
        return x.strftime('%d/%m/%Y')
    except AttributeError:
        return x
    except Exception:
        raise

for i in list_of_possible_date_columns:
    df[i] = df[i].apply(undate)

Answer 2

• Using converters{'Date': str} option inside the pandas.read_excel which helps. pandas.read_excel(xlsx, sheet, converters={'Date': str})
• you can try convert your timestamp back to the original format
  df['Date'][0].strftime('%Y/%m/%d')