AssertionError class numpy ndarray

Question

I am having Time Series data in my data frame (dataset) after indexing by date when I am trying to call any value by date am getting an error of 

AssertionError: <class 'numpy.ndarray'> please help me.

Please follow below for code:

# Import libraries

import pandas as pd

import numpy as np

import matplotlib.pyplot as plt

import math

%matplotlib nbagg

# Upload Dataset

dataset = pd.read_csv("Data.csv")

dataset.head()

Ticker Per Date Time Open High Low Close Volume

0 1.HK 5 20200706 33000 52.00 52.55 51.80 52.20 739591

1 1.HK 5 20200706 33500 52.20 52.55 52.15 52.55 216500

2 1.HK 5 20200706 34000 52.55 52.85 52.50 52.80 430000

3 1.HK 5 20200706 34500 52.80 52.95 52.75 52.90 316925

4 1.HK 5 20200706 35000 52.90 53.05 52.85 53.00 473288

# Adding New Column with Date and time

dataset['Datetime'] = dataset['Date'].astype(str) + ' ' + dataset['Time'].astype(str)

# Changing datetime column format into datetime Format

dataset['Datetime'] = pd.to_datetime(dataset['Datetime'],format='%Y%m%d %M%f')

dataset['Date'] = pd.to_datetime(dataset['Date'],format='%Y%m%d')

dataset['Time'] = pd.to_datetime(dataset['Time'],format= '%M%f')

# setting the index

dataset.set_index("Datetime",inplace = True)

dataset['2020-07-06']

---------------------------------------------------------------------------

AssertionError                            Traceback (most recent call last)

<ipython-input-8-9132c41bc610> in <module>

----> 1 dataset['2020-07-06']

~\anaconda3\lib\site-packages\pandas\core\frame.py in __getitem__(self, key)

   2883             # either we have a slice or we have a string that can be converted

   2884             #  to a slice for partial-string date indexing

-> 2885             return self._slice(indexer, axis=0)

   2886

   2887         # Do we have a (boolean) DataFrame?

~\anaconda3\lib\site-packages\pandas\core\generic.py in _slice(self, slobj, axis)

   3555         Slicing with this method is *always* positional.

   3556         """

-> 3557         assert isinstance(slobj, slice), type(slobj)

   3558         axis = self._get_block_manager_axis(axis)

   3559         result = self._constructor(self._mgr.get_slice(slobj, axis=axis))

AssertionError: <class 'numpy.ndarray'>

Answer 1

Same problem here bro!

Comments

Hi@Bijoy,

You need to follow the format of your dataset. In the dataset check the date column. In that, no hyphen is there. But at the time of extracting data, you are feeding hyphens.

dataset['2020-07-06']

So, just use the exact format that you have in your dataset. If it is in a string, then use the string at the time of data extraction.