After updating to pandas 1.4, I now receive the following warning when using frame.append to append a dictionary to a Pandas DataFrame.
FutureWarning: The frame.append method is deprecated and will be
removed from pandas in a future version. Use pandas.concat instead.
Below is the code. This still works, though I would like to resolve the warning.
report = report.append({
"period":period,
"symbol":symbol,
"start_date":start_date,
"start_price":start_price,
"start_market_cap":start_market_cap,
"end_date":end_date,
"end_price":end_price,
"end_market_cap":end_market_cap,
"return":return_
},ignore_index=True)
I have updated the code to the below, which kicks a different warning:
report = pd.concat([report,{
"period":period,
"symbol":symbol,
"start_date":start_date,
"start_price":start_price,
"start_market_cap":start_market_cap,
"end_date":end_date,
"end_price":end_price,
"end_market_cap":end_market_cap,
"return":return_
}],ignore_index=True)
TypeError: cannot concatenate object of type '<class 'dict'>'; only Series and DataFrame objs are valid
2 questions: Is the first warning wrong? What is the pandas 1.4 way to achieve this? Thanks.
Use loc to assign a single row value:
report.loc[len(report)] = {"period":period,
"symbol":symbol,
"start_date":start_date,
"start_price":start_price,
"start_market_cap":start_market_cap,
"end_date":end_date,
"end_price":end_price,
"end_market_cap":end_market_cap,
"return":return_
}