Programmer Humor

i and I are acceptable in small loops. But it depends a lot on the language used. If you're in C or bash maybe it's fine. But if you're in a higher level language like C# you usually have built on functions for iterating over something.

For example you have a list of movies you want to get the rating from, instead of doing

for (i = 0; i < movies.length; i++)
    var movie = movies[i]
    ....

Its often more readable to do

movies.forEach { movie -> 
    var rating = movie.rating
    ....
}

Also if you work with tables it can be very helpful to name your iteration variables as row and column.

It's all about making it readable, understandable, and correct. There's no point having comments if you forget to update them when you change the code. And you better make sure the AI comments on the 2000 lines of three letter variables is correct!