Обработка символьных строк

with open(r'путь к файлу') as reader:
    
    f = reader.read()
    count_max = 0
    lit = f[0]
    lit_out = ''
 
    for elem in f[1:]:
        
        if elem in lit:
            lit += elem 
 
        elif elem not in lit:
 
            if len(lit) > count_max:
 
                count_max = len(lit)
                lit_out = lit[0]   
 
            lit = elem
    
print(lit_out, count_max)

with open('file.txt') as f:
    data = f.read()
 
end = len(data)
start = 0
res = []
while start < end:
    line = data[start]
    for _ in range(start, end):
        start += 1 
        if  start != end and data[start ] in line :
            line += data[start ]
        else:
            res.append(line)
            break
result = max(res, key = len)
print(result[0],len(result))

result, maximum = "", 0
symbol, count = "", 0
for current in text:
    if current != symbol:
        if count > maximum:
            result, maximum = symbol, count
        symbol, count = current, 0
    count += 1
 
print(result, maximum)

result, maximum = "", 0
symbol, count = "", 0
for current in 'XXXYZXYXXYYZXYXZZZZXXXXX':
    if current != symbol:
        if count > maximum:
            result, maximum = symbol, count
        symbol, count = current, 0
    count += 1
 
print(result, maximum)

with open('file.txt') as f:
    data = f.read()
 
 
symb = data[0]
res = data[0]
count_max = 0
temp_max = 0
 
for analog  in data:
    if analog == symb:
        temp_max += 1
        continue
    if temp_max > count_max:
            count_max = temp_max
            res = symb
    temp_max = 1
    symb = analog
   
if temp_max > count_max:
    count_max = temp_max
    res = symb
print(res, count_max)

import re
 
with open('in.txt', 'r') as f_in:
    answer = max([i.group() for i in re.finditer(r'(?i)(\w)\1+', f_in.read())], key=len)
    print(f'{answer[0]} {len(answer)}')