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pythonpandasdataframequandl

How to reference a dataframe name as a string in a for loop?

Here is my code.

import numpy as np
import pandas as pd
import matplotlib.pyplot as plt
import quandl

start = pd.to_datetime('2012-01-01')
end = pd.to_datetime('2017-01-01')



aapl = quandl.get('WIKI/aapl.11', start_date = start, end_date= end )
csco = quandl.get('WIKI/csco.11', start_date = start, end_date= end )
ibm = quandl.get('WIKI/ibm.11', start_date = start, end_date= end )
amzn = quandl.get('WIKI/amzn.11', start_date = start, end_date= end )

This creates 4 data frames. I want to be able to achieve this by using a for loop.

Here is what I imagine the for loop would look like.

for i in [aapl,csco,ibm,amzn]:
    a = 'WIKI/'+ i + '.11'
    i = quandl.get(a, start_date=start, end_date=end)

I would like to be able to reference the name of the data frame as a string in the loop to perform other functions that require the name of the dataframe as a string.

Anyone help me with this or suggest an alternative approach which achieve the same result. I am hoping to be able to do this in a way that would scale to 100s of loop iterations.

Thank you for your help.

Solution

  • Equivalent to G. B.'s answer, but without dictionary comprehension in case you are not familiar with it yet.

    import pandas as pd
import quandl

start = pd.to_datetime('2012-01-01')
end = pd.to_datetime('2017-01-01')

data = {}

for key in ['aapl', 'csco', 'ibm', 'amzn']:
    name = 'WIKI/'+ key + '.11'
    data[key] = quandl.get(name, start_date=start, end_date=end)

# Then you can use it like
data['aapl'].DoSomething()