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efueyo
Asked: 2022-07-08 13:54:14 +0800 CST 2022-07-08 13:54:14 +0800 CST

Problem with the length of a dictionary

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I import the following quotes into a DataFrame.

import pandas as pd
import numpy as np
from pandas_datareader import data as pdr
import yfinance as yf
yf.pdr_override() # <== that's all it takes :-)

# download dataframe
datos = pdr.get_data_yahoo("SPY", start="2000-01-01", end="2021-04-30")
datos.shape[0]

The statement datos.shape[0]returns the number of records in the DataFrame, which in this case is 5366. Next I convert the DataFrame to a dictionary and try to get it to return the number of elements in the dictionary.

data = datos.to_dict()
len(data)

It returns me 6, which is wrong. What is my fault? I will appreciate help.

python

1 Answers

  1. Best Answer

    It returns me 6, which is wrong. What is my fault? I will appreciate help.

    The error is understanding, the returned result is correct , when you use len()on a dictionary it returns the number of keys that said dictionary has (which correspond to the columns of your DataFrame) and you have six columns/keys.

    Bonuses

    If you want to work on a data table (making counts, averages, extracting lengths) I recommend you stick with the format DataFramesince a dictionary will be more complicated to work with.

    I would only use the dictionary in situations of memory or time constraints.

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