Iteration, while loop, and for loop

[Grant Edwards]

On 2016-06-28, Tim Chase <python.list at tim.thechases.com> wrote:
> On 2016-06-29 01:20, Steven D'Aprano wrote:
>> While loops are great for loops where you don't know how many
>> iterations there will be but you do know that you want to keep
>> going while some condition applies:
>> 
>> while there is still work to be done:
>>     do some more work
>
> I find this particularly the case when the thing being iterated over
> can be changed, such as a queue of things to process:
>
>   items = deque()
>   items.append(root_node)
>   while items:
>     item = items.popleft()
>     process(item)
>     items.extend(item.children)

Yep, I often do something similar when processing a block of data
bytes comprising a sequence of "things" of varying number of bytes.

    data = read_a_blob_of_bytes()
    while data:
        #figure out how long the first "thing" is
        len = <some expression typically involving the first few bytes of 'data'>  
        handle_thing(data[:len])
        data = data[len:]
> But then, if you wrap up your "while" loop as a generator that yields
> things, you can then use it in a "for" loop which seems to me like
> the Pythonic way to do things. :-)

Yea, I keep telling myself that, but I never actually do it.

-- 
Grant Edwards               grant.b.edwards        Yow! How do I get HOME?
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