List of strings I want to group together if they contain a specific substring from a master list-CodePudding

I have list of strings that I want to group together if they contain a specific substring from a master list.

Example Input:

["Audi_G71Q3E5T7_Coolant", "Volt_Battery_G9A2B4C6D8E", "Speaker_BMW_G71Q3E5T7", "Engine_Benz_G9A2B4C6D8E", "Ford_G9A2B4C6D8E_Wheel", "Toyota_Exhaust_G71Q3E5T7"]

Master List:

["G71Q3E5T7", "G9A2B4C6D8E"]

Expected Output:

[["Audi_G71Q3E5T7_Coolant", "Speaker_BMW_G71Q3E5T7", "Toyota_Exhaust_G71Q3E5T7"], ["Volt_Battery_G9A2B4C6D8E", "Engine_Benz_G9A2B4C6D8E", "Ford_G9A2B4C6D8E_Wheel"]]

I haven't found any example or solution online but am aware the itertools.groupby() function is useful in these scenarios, but am struggling to make it work.

CodePudding user response：

Example inputs:

in_list = ["Audi_G71Q3E5T7_Coolant", "Volt_Battery_G9A2B4C6D8E", "Speaker_BMW_G71Q3E5T7",
           "Engine_Benz_G9A2B4C6D8E", "Ford_G9A2B4C6D8E_Wheel", "Toyota_Exhaust_G71Q3E5T7"]
master_list = ["G71Q3E5T7", "G9A2B4C6D8E"]
out_list = []

For every master item, check if is in any input item. Add results to out_list[index]

for index, m in enumerate(master_list):
    out_list.append([])
    for i in in_list:
        if m in i:
            out_list[index].append(i)

print(out_list)

CodePudding user response：

itertools.groupby is not appropriate as you would need to sort the data.

You can use a regex to extract the IDs, and a dictionary/defaultdict to collect the data:

L = ["Audi_G71Q3E5T7_Coolant", "Volt_Battery_G9A2B4C6D8E",
     "Speaker_BMW_G71Q3E5T7", "Engine_Benz_G9A2B4C6D8E",
     "Ford_G9A2B4C6D8E_Wheel", "Toyota_Exhaust_G71Q3E5T7"]
ids = ["G71Q3E5T7", "G9A2B4C6D8E"]

import re
from collections import defaultdict

regex = re.compile('|'.join(map(re.escape, ids)))
# re.compile(r'G71Q3E5T7|G9A2B4C6D8E', re.UNICODE)

out = defaultdict(list)

for item in L:                 # for each item
    m = regex.search(item)     # try to find ID
    if m:                      # if ID
        out[m.group()].append(item)  # add to appropriate list
        
out = list(out.values())

output:

[['Audi_G71Q3E5T7_Coolant',
  'Speaker_BMW_G71Q3E5T7',
  'Toyota_Exhaust_G71Q3E5T7'],
 ['Volt_Battery_G9A2B4C6D8E',
  'Engine_Benz_G9A2B4C6D8E',
  'Ford_G9A2B4C6D8E_Wheel']]