date        path
2017-01-01  /A/B/C/D
2017-01-01  /X
2017-01-01  /X/Y

date        path
2017-01-01  /A/B
2017-01-01  /X
2017-01-01  /X/Y

from urllib import quote_plus

path_levels = df['path'].split('/')
filtered_path_levels = []
for _level in range(min(df_size, 3)):
    # Take only the top 2 levels of path
    filtered_path_levels.append(quote_plus(path_levels[_level]))

df['path'] = '/'.join(map(str, filtered_path_levels))

path_levels = split(results_df['path'], '/')
filtered_path_levels = []
for _level in range(size(df_size, 3)):
    # Take only the top 2 levels of path
    filtered_path_levels.append(quote_plus(path_levels[_level]))

df['path'] = '/'.join(map(str, filtered_path_levels))

ValueError: Cannot convert column into bool: please use '&' for 'and', '|' for 'or', '~' for 'not' when building DataFrame boolean expressions.