Using Pandas dataframe to process list data get loc error

Question

I'm using Pandas to process List data. The list data is

[(datetime.date(1992, 2, 1), 114535.0), (datetime.date(1992, 3, 1), 120025.0), (datetime.date(1992, 4, 1), 124470.0), (datetime.date(1992, 5, 1), 125822.0), (datetime.date(1992, 6, 1), 122834.0)]

I create labels and use DataFrame.from_records to read the data

labels = ['date', 'value']
df = pd.DataFrame.from_records(listData, columns=labels)

df = df.set_index('date')
print(df.loc['1992-03-01'])

I got the following error using df.loc

  File "/usr/lib64/python3.6/site-packages/pandas/core/indexes/base.py", line 2890, in get_loc
    return self._engine.get_loc(key)
  File "pandas/_libs/index.pyx", line 107, in pandas._libs.index.IndexEngine.get_loc
  File "pandas/_libs/index.pyx", line 131, in pandas._libs.index.IndexEngine.get_loc
  File "pandas/_libs/hashtable_class_helper.pxi", line 1607, in pandas._libs.hashtable.PyObjectHashTable.get_item
  File "pandas/_libs/hashtable_class_helper.pxi", line 1614, in pandas._libs.hashtable.PyObjectHashTable.get_item
KeyError: '1992-03-01'

You have datetime objects in a pd.Index index, so you have to access the index with datetime - df.loc[datetime.date(1992,3,1)]. You could use strings directly if you had pd.DatetimeIndex — rafaelc
– rafaelc, Commented Oct 7, 2019 at 13:42

jezrael · Accepted Answer · 2019-10-07 13:48:28Z

2

Create DatetimeIndex with to_datetime for convert dates objects to timestamps:

labels = ['date', 'value']
df = pd.DataFrame.from_records(listData, columns=labels)

df['date'] = pd.to_datetime(df['date'])
df = df.set_index('date')
print(df.loc['1992-03-01'])
value    120025.0
Name: 1992-03-01 00:00:00, dtype: float64

Or looking by date objects:

labels = ['date', 'value']
df = pd.DataFrame.from_records(listData, columns=labels)

df = df.set_index('date')
print(df.loc[datetime.date(1992, 3, 1)])
value    120025.0
Name: 1992-03-01, dtype: float64

edited Oct 7, 2019 at 13:48

answered Oct 7, 2019 at 13:40

jezrael

868k103 gold badges1.4k silver badges1.3k bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Using Pandas dataframe to process list data get loc error

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related