What is the execution process of a for loop in Python?

In Python, the execution flow of a for loop is as follows:

1. First, determine the object to iterate over (also known as iterable), which can be a sequence (such as a list, tuple, or string) or an iterator (such as a range object).
2. Then, one by one, retrieve elements from the iterable object and assign them to the loop variable.
3. Execute the code block within each iteration, handling the current element.
4. Repeat the above steps until all elements are traversed or a certain termination condition is met.

Specifically, the execution process of a for loop is as follows:

1. Firstly, initialize the loop variable. Before the loop begins, assign the loop variable to the first element of the iterable object.
2. Execute the code block within the loop. The code block can operate on the current element.
3. Check the loop condition. If the condition is met, continue with the next iteration of the loop; otherwise, exit the loop.
4. Update the loop variable to the next element of the iterable object.
5. Repeat steps 2-4 until all elements have been traversed or a certain termination condition is met.

It is important to note that when using a for loop to iterate over an iterator, the loop variable is updated based on the output of the iterator each time through the loop, rather than fetching all elements at once like a sequence. This can save memory when processing large data sets.