CODEWITHSUNDEEP
pythonpandascsvanaconda
Sebastian Schmidt
Sebastian Schmidt

Reputation: 37

Pandas won´t create .csv file

I recently started diving into algo trading and building a bot for crypto trading.

For this i created a backtester with pandas to run different strategies with different parameters. The datasets (csv files) I use are rather larger (around 40mb each).

These are processed, but as soon as i want to save the processed data to a csv, nothing happens. No output whatsoever, not even an error message. I tried to use the full path, I tried to save it just with the filename, I even tried to save it as a .txt file. Nothing seems to work. I also tried the solutions I was able to find on stackoverflow.

I am using Anaconda3 in case that could be the source of my problem.

Here you can find the part of my code ,which tries to save the dataframe to a file.

results_df = pd.DataFrame(results) 
results_df.columns = ['strategy', 'number_of_trades', "capital"]    
print(results_df)
for i in range(2, len(results_df)):
    if results_df.capital.iloc[i] < results_df.capital.iloc[0]:
        results_df.drop([i],axis="index")
        #results to csv
        current_dir = os.getcwd()
        results_df.to_csv(os.getcwd()+'\\file.csv')
        print(results_df)

Thank you for your help!

Upvotes: 0

Views: 299

Answers (1)

jottbe
jottbe

Reputation: 4521

You can simplifiy your code by a great deal and write it as (should also run faster):

results_df = pd.DataFrame(results) 
results_df.columns = ['strategy', 'number_of_trades', "capital"]    
print(results_df)

first_row_capital= results_df.capital.iloc[0]
indexer_capital_smaller= results_df.capital < first_row_capital

values_to_delete= indexer_capital_smaller[indexer_capital_smaller].index
results_df.drop(index=values_to_delete, inplace=True)

#results to csv
current_dir = os.getcwd()
results_df.to_csv(os.getcwd()+'\\file.csv')
print(results_df)

I think, the main problem in your code might be, that you write the csv each time you found an entry in the dataframe where capital sattisfies the condition and you write it only if you find such a case.

And if you just do the deletion for the csv output but don't need the dataframe in memory anymore, you can make it even simpler:

results_df = pd.DataFrame(results) 
results_df.columns = ['strategy', 'number_of_trades', "capital"]    
print(results_df)

first_row_capital= results_df.capital.iloc[0]
indexer_capital_smaller= results_df.capital < first_row_capital

#results to csv
current_dir = os.getcwd()
results_df[indexer_capital_smaller].to_csv(os.getcwd()+'\\file.csv')
print(results_df[indexer_capital_smaller])

This second variant only applies a filter before writing the filtered lines and before printing the content.

Upvotes: 1

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