How to explode a list inside a Dataframe cell into separate rows

Question

I\'m looking to turn a pandas cell containing a list into rows for each of those values.

So, take this:

If I\'d like to unpack and stack the value

Answer 1

Here is a potential optimization for larger dataframes. This runs faster when there are several equal values in the "exploding" field. (The larger the dataframe is compared to the unique value count in the field, the better this code will perform.)

def lateral_explode(dataframe, fieldname): 
    temp_fieldname = fieldname + '_made_tuple_' 
    dataframe[temp_fieldname] = dataframe[fieldname].apply(tuple)       
    list_of_dataframes = []
    for values in dataframe[temp_fieldname].unique().tolist(): 
        list_of_dataframes.append(pd.DataFrame({
            temp_fieldname: [values] * len(values), 
            fieldname: list(values), 
        }))
    dataframe = dataframe[list(set(dataframe.columns) - set([fieldname]))]\ 
        .merge(pd.concat(list_of_dataframes), how='left', on=temp_fieldname) 
    del dataframe[temp_fieldname]

    return dataframe