Looping through dates with a for loop

Question

I am trying to loop through all the dates for the given time period with:

disp_start = dt.datetime(2017,1,6)           #####START DATE
disp_data = closingprices.loc[disp_start:]   #closing prices is data w/ stock prices  

for date in disp_data.index:
    returns = (closingprices.iloc[-1].divide(closingprices.iloc[date]))-1

But get this error:

TypeError: cannot do positional indexing on <class 'pandas.core.indexes.datetimes.DatetimeIndex'> with these indexers [2017-01-06 00:00:00] of <class 'pandas._libs.tslib.Timestamp'>

Not sure how to loop through all periods from a given start date (disp_start). Thanks

do you need `loc` like `closingprices.loc[date]` ? – jezrael Jul 25 '17 at 06:42 — jezrael, Jul 25 '17 at 06:42
iloc is only for integer positions – CrazyElf Jul 25 '17 at 06:44 — CrazyElf, Jul 25 '17 at 06:44

jezrael · Accepted Answer · 2017-07-25T07:00:11.033

1

I think you need DataFrame.loc for select by label, because DataFrame.iloc is for select by position(s):

for date in disp_data.index:
    returns = (closingprices.iloc[-1].divide(closingprices.loc[date]))-1

If need iloc for some reason is posssible use Index.get_loc:

for date in disp_data.index:
    returns = (closingprices.iloc[-1].divide(closingprices.iloc[df.index.get_loc(date)]))-1

edited Jul 25 '17 at 07:00

answered Jul 25 '17 at 06:45

jezrael

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score 0 · Answer 2 · answered Jul 25 '17 at 06:43

 def daterange(start_date, end_date):
    for n in range(int ((end_date - start_date).days)):
       yield start_date + timedelta(n)

start_date = date(2013, 1, 1)
end_date = date(2015, 6, 2)
for single_date in daterange(start_date, end_date):
print single_date.strftime("%Y-%m-%d")

Iterating through a range of dates in Python

Looping through dates with a for loop

2 Answers2