The tell() method

The tell() method answers a simple question: "Where exactly am I in this file right now?" When you read from or write to a file, the file object keeps track of its current position — like a cursor that moves forward as you work. tell() returns that position as an integer, measured in bytes from the very start of the file.

The syntax is straightforward:

file_object.tell()

No arguments are needed. The method simply reports the byte offset of the file object's current location.

What the returned number means:

The integer returned by tell() is the number of bytes from the beginning of the file up to the current position of the file object. For example, if you have just opened a file and haven't read anything yet, tell() returns 0 — you are at the start. As you read or write more of the file, the number grows to reflect how far the file object has moved.

Why this matters:

• It helps you keep track of where you are during sequential reading or writing.
• It is essential when you need to jump to a specific location using seek() — you first use tell() to know your current position, then decide where to go.
• It is useful for debugging: if your program behaves unexpectedly while reading a file, tell() can confirm whether the file object is positioned where you think it is. …