Removing substrings in list of list of strings, maintain order - Python

Question

I have a list of lists with strings.

words = [['gamma_ray_bursts','merger','death','throes','magnetic_flares','neutrino_antineutrino','objections','bursts','double_neutron_star','parker_instability','positrons'],
 ['dot','gravitational_lensing','splittings','limits','amplifications','time_delays','extracting_information','fix','distant_quasars'],
 ['recoil','gamma_ray_bursts','neutron_stars','jennings','possible_origins','birthplaces','disjoint','arrival_directions'],
 ['sn_sn','type_ii_supernovae','distances','dilution','extinction','extragalactic_distance_scale','expanding_photosphere','distance','photospheres','supernovae_sn','span_wide_range'],
 ['photon_pair','high_energy','gamma_ray_burst','optical_depth','absorbing_medium','implications','problem','annihilation_radiation','emergent_spectrum','limit','radiation_transfer','collimation','regions']]

I would like to remove any elements of a list if it is a substring of another element.
I would like the order preserved

' I have tried this loop:

for string_list in words:
    for item in string_list: 
        for item1 in string_list:
            if item in item1 and item!= item1:
                string_list.remove(item)

It seems to work with smaller list of lists but outputs an error when I increase the len of the list.

ValueError                                Traceback (most recent call last)
<ipython-input-91-7546f608171f> in <module>
      4         for item1 in string_list:
      5             if item in item1 and item!= item1:
----> 6                 string_list.remove(item)

ValueError: list.remove(x): x not in list

expected output:

words = [['gamma_ray_bursts','merger','death','throes','magnetic_flares','neutrino_antineutrino','objections','double_neutron_star','parker_instability','positrons'], ['dot','gravitational_lensing','splittings','limits','amplifications','time_delays','extracting_information','fix','distant_quasars'],['recoil','gamma_ray_bursts','neutron_stars','jennings','possible_origins','birthplaces','disjoint','arrival_directions'], ['sn_sn','type_ii_supernovae','distances','dilution','extinction','extragalactic_distance_scale','expanding_photosphere','photospheres','supernovae_sn','span_wide_range'],['photon_pair','high_energy','gamma_ray_burst','optical_depth','absorbing_medium','implications','problem','annihilation_radiation','emergent_spectrum','limit','radiation_transfer','collimation','regions']]

I've searched the forums, there is a very similar question and the solution works sometimes but other times it outputs an error, it's not consistent where this error occurs. The length of the list is variable. Python - Remove any element from a list of strings that is a substring of another element

Please add the desired output. You question can be interpreted in multiple ways. What do you mean by "substring of another element."? You of a list of lists of strings. Are you working with substrings from the strings? I am confused. Also what is an element? Are you referring to the other lists? — Error - Syntactical Remorse
– Error - Syntactical Remorse, Commented Dec 11, 2019 at 13:45
its never good practice to change the contents of a list that you are trying to iterate over — Chris Doyle
– Chris Doyle, Commented Dec 11, 2019 at 13:53
Sorry, I added the expected output. Within each list, I would like to remove any element/string that is a substring of another element/string. Ex. list_1 = ['gamma_ray_bursts' ,... 'bursts'] remove 'bursts' output = ['gamma_ray_bursts',...] Each list of list should be checked for substrings independently. No. I'm referring to elements within each list, not to the other lists. — Greg
– Greg, Commented Dec 11, 2019 at 13:56
@ChrisDoyle I was wondering that. If that's the case, creating a new list without the substrings is better/acceptable practice? — Greg
– Greg, Commented Dec 11, 2019 at 13:58
so just to clarify your requirement, you want to remove any element of a list if its a sublist of another item in the same list. — Chris Doyle
– Chris Doyle, Commented Dec 11, 2019 at 14:03

Jarvis · Accepted Answer · 2019-12-11 14:06:42Z

Instead of removing elements from a list, why not create a new one matching your requirements (since being safer)?

# method to filter out substrings
def substr_in_list(elem, lst):
  for s in lst:
    if elem != s and elem in s:
      return True
  return False

words = [[j for j in i if not substr_in_list(j, i)] for i in words]

Output :

[['gamma_ray_bursts', 'merger', 'death', 'throes', 'magnetic_flares', 'neutrino_antineutrino', 'objections', 'double_neutron_star', 'parker_instability', 'positrons'], ['dot', 'gravitational_lensing', 'splittings', 'limits', 'amplifications', 'time_delays', 'extracting_information', 'fix', 'distant_quasars'], ['recoil', 'gamma_ray_bursts', 'neutron_stars', 'jennings', 'possible_origins', 'birthplaces', 'disjoint', 'arrival_directions'], ['sn_sn', 'type_ii_supernovae', 'distances', 'dilution', 'extinction', 'extragalactic_distance_scale', 'expanding_photosphere', 'photospheres', 'supernovae_sn', 'span_wide_range'], ['photon_pair', 'high_energy', 'gamma_ray_burst', 'optical_depth', 'absorbing_medium', 'implications', 'problem', 'annihilation_radiation', 'emergent_spectrum', 'limit', 'radiation_transfer', 'collimation', 'regions']]

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