Convert nested list into dict with key and multiple list values if exist

Question

I have a nested list as below. Since list is very huge and to reduce search time, thought would be better to convert as dict.

With innerlist[index] to be key and rest to be values. Incase key is occuring twice need to add list of values in dict.

List

[
 ['001', 'xxxx', 'xxxx'], 
 ['002', '1', 'H', '0', 'H'], 
 ['002', '1', 'Z', '0', 'H']
]

Need Dict as follows

   {
        '001': ['xxxx', 'xxxx'],
        '002': [
                ['1', 'H','0', 'H'],
                ['1', 'Z','0', 'H']
        ],
    }

I did it with following code, still seems not an optimum way for a huge list. Also for non duplicated item, I get nested list with 1 item. '001': [['xxxx', 'xxxx']], Let me know if a better way is possible.

data_dict = dict()
for data in bytes_data:
    if data[0] in data_dict:
        data_dict[data[0]].append(data[1:])
    else:
        data_dict[data[0]] = [data[1:]]

Answer 1

If you're in a recent Python version (3.5+ I think) you can do this more concisely like:

data = [
  ['001', 'xxxx', 'xxxx'],
  ['002', '1', 'H', '0', 'H'],
  ['002', '1', 'Z', '0', 'H']
]

data_dict = {}

for key, *vals in data:
    data_dict.setdefault(key, []).append(vals)

But I suggest benchmarking it, the code you have may be more efficient, especially if many of the keys do not have repeat entries in the src list.