Выведите средний балл по каждому предмету.

fn = r'f:/123/hello.txt'
peoples = {}
with open (fn) as f:
    onstring = [e.rstrip() for e in f]
    print(onstring)
for items in onstring:
    lessons = items.split(" ")[1]
    bal = items.split(" ")[2]
    if lessons in peoples:
        peoples[lessons].append(int(bal))
    else:
        peoples[lessons] = [int(bal)]
print(peoples)
f.close()
for lessons, bal in peoples.items():
    print(f"{lessons} {sum(bal) / len(bal):.1f}")

>>> def lesson_name(value):
...     return ' '.join(value.split()[1:-1])
...
>>> lesson_name('Козлов история 5')
'история'
>>> lesson_name('Козлов Русский язык 5')
'Русский язык'

return ' '.join(value.split()[1:-1])

fn = r'f:/123/hello.txt'
peoples = {}
with open (fn) as f:
    onstring = [e.rstrip() for e in f]
    print(onstring)
for items in onstring:
    lessons = " ".join(items.split()[1:-1])
    bal = items.split(" ")[-1]
    if lessons in peoples:
        peoples[lessons].append(int(bal))
    else:
        peoples[lessons] = [int(bal)]
print(peoples)
f.close()
for lessons, bal in peoples.items():
    print(f"{lessons} {sum(bal) / len(bal):.1f}")

# -*- coding: utf-8 -*-
 
my_list = ["first", "second", "third"]
 
print(" +=+ ".join(my_list)) # first +=+ second +=+ third
 
def join(collection:list, sep:str)->str:
    result = ""
    for value in collection[: -1]:
        result += str(value) + sep
    return result + collection[-1]
 
print(join(my_list, " +||+ ")) # first +||+ second +||+ third