Reminder of add_columns implementation

[zbarry]

For myself, mostly:

Chaining implementation:

import pandas_flavor as pf

@pf.register_dataframe_method
def add_columns(df, **kwargs):
    # column already exists
    # v is not a scalar but is a different length from the dataframe
    
    for k, v in kwargs.items():
        df = df.add_column(k, v)
    return df

Example usage for copying repeating rows from a DataFrame into another:

df1.columns is of {'var1', 'var2', 'var3'}

column_order = ['var1', 'var2']

df2.add_columns(**{
    col: vals
    for col, vals in zip(column_order, df1[column_order].iloc[0]) 
})

[ericmjl]

http://pandas.pydata.org/pandas-docs/stable/generated/pandas.DataFrame.assign.html

It appears add_columns can simply function as a syntactic sugar wrapper for assign. Fulfills the goal of a cleaner or more explicit API.

[zbarry]

We should confirm assign doesn't copy the underlying data.

[zbarry]

assign indeed copies the underlying data:

shrug.

I'll move forward with the implementation we came up with.

[zbarry]

🥇