Pandas unlistfy one colum

unlistfy.py

df['new'] = df['new'].str.split('/') # example how to listfy a column of strings
temp = pd.DataFrame(df['new'].dropna().tolist())

temp = temp.stack()
temp.index = temp.index.droplevel(1) # index need to be coherent with the original dataframe
temp.name = 'new_colum' # name of the new column in the original dataframe

df = df.join(temp)