I have a pandas DataFrame with 4 columns and I want to create a new DataFrame that only has three of the columns. This question is similar to: Extracting specific columns from a data frame but for pandas not R. The following code does not work, raises an error, and is certainly not the pandasnic … Read more
When selecting a sub dataframe from a parent dataframe, I noticed that some programmers make a copy of the data frame using the .copy() method. For example, X = my_dataframe[features_list].copy() …instead of just X = my_dataframe[features_list] Why are they making a copy of the data frame? What will happen if I don’t make a copy? … Read more
Background I just upgraded my Pandas from 0.11 to 0.13.0rc1. Now, the application is popping out many new warnings. One of them like this: E:\FinReporter\FM_EXT.py:449: SettingWithCopyWarning: A value is trying to be set on a copy of a slice from a DataFrame. Try using .loc[row_index,col_indexer] = value instead quote_df[‘TVol’] = quote_df[‘TVol’]/TVOL_SCALE I want to know … Read more
I have the following indexed DataFrame with named columns and rows not- continuous numbers: a b c d 2 0.671399 0.101208 -0.181532 0.241273 3 0.446172 -0.243316 0.051767 1.577318 5 0.614758 0.075793 -0.451460 -0.012493 I would like to add a new column, ‘e’, to the existing data frame and do not want to change anything in … Read more
