Add a date column to csv using python

Question

I have the following code which writes a data output to a csv file. I want to add a date variable at the end of each row using the yesterday.strftime variable that i am using in creating the filename. For example:

Thanks!

my current output is like:

columnA

1

2

and I want to add the following column:

Date

2/5/2016

. . .

CODE::

filepath = 'C:\\test\\'   
filename = yesterday.strftime('%Y-%m-%d') + '_' + 'test.csv'

f = open( filename, 'wt')
writer = csv.writer(f, lineterminator='\n')
header = [h['name'][3:] for h in results.get('columnHeaders')] 
writer.writerow(header)
print(''.join('%30s' % h for h in header))

# Write data table.
if results.get('rows', []):
  for row in results.get('rows'):
    writer.writerow(row)
    print(''.join('%30s' % r for r in row))

else:
  print ('No Rows Found')

f.close()

Where does results come from? You might have to look there — putvande
– putvande, Commented Feb 5, 2016 at 19:00
FYI, you can replace if results.get('rows', []):, for row in results.get('rows'): with just if results.get('rows'):, for row in results['rows']:; the first usage doesn't use the default for anything but a boolean test (so the default default of None is fine), and the second already knows the key exists, so no need to use .get at all. — ShadowRanger
– ShadowRanger, Commented Feb 5, 2016 at 19:39

LetMeSOThat4U · Accepted Answer · 2016-02-05 21:06:01Z

1

In [26]: import pandas as pd

In [27]: import datetime

In [28]: a = pd.read_csv('a.csv')

In [29]: a
Out[29]: 
columnA
0        1
1        2

In [30]: a['Date'] = [datetime.date.today()]*len(a)

In [31]: a
Out[31]: 
columnA        Date
0        1  2016-02-05
1        2  2016-02-05

In [32]: a.to_csv('adate.csv')

Generally: https://www.airpair.com/python/posts/top-mistakes-python-big-data-analytics

answered Feb 5, 2016 at 21:06

LetMeSOThat4U

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1 Comment

Hamed Jafari Over a year ago

First off thanks for posting. I ran the code, but it's adding an index field of some sort to the beginning of my file. Is there a way for me to omit that or give it a name? currently it's just blank.

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