file.tell stuff (3.X)

tell_test.py

with open("test.txt", "w") as w:
    w.write("""
    this is a test
    this is another test
    another test""")
with open("test.txt", "rb") as e: # when using a for loop or next/basically going through the file, using file.tell only works with "rb", but if you use "r" with a for loop + file.tell, then an error occur
    for i in e:
        print(e.tell())

with open("test.txt", "r") as e: # works since there no for loop/next call
    print(e.tell())

with open("test.txt", "r") as e: # error here
    for i in e:
        print(e.tell())