Fastest way to count contiguously chars

Question

I have a text string like:

33 P DDD AA 00 23

I've created a code that works well, but I'm searching for other methods to do that.

translate_dict = {
   ...
}    

result = []
i = 0

while i < len(t):
    counter = 1
    while i+counter < len(t) and t[i] == t[i+counter]:
        counter +=1
    result.append(translate_dict.get(t[i], t[i]) + str(counter))
    i += counter
    
return ''.join(result)

Answer 1

Here's one possible optimization:

def f2(t):
    res = []
    last = t[0]
    counter = 0
    duration = 0
    tr = translate_dict.get

    for c in t:
        if c == last:
            counter += 1
            continue
        res.append(tr(last, last) + str(counter))
        duration += counter
        last = c
        counter = 1

    res.append(tr(last, last) + str(counter))
    duration += counter

    return ''.join(res), duration

Shows ~ 2x improvement on my machine.