Loop-and-a-half (Re: Curious assignment behaviour)

[Alex Martelli]

Paul Rubin wrote:
        ...
>> for line in file.xreadlines():
>>    ...
> 
> What if you want to read until you get to a delimiter?
> 
>   while (line := readline()) != 'end': ...

for line in file.xreadlines():
    if line == 'end': break
    etcetc(line)

Of course, if you're transliterating from some other language and need to 
keep close structure similarity (e.g. for didactic reasons), Python makes 
that easy too, see e.g. the rather obvious approach of my recipe:

http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/66061

which would give:

while data.set(file.readline()) != 'end':
    process(data.get())


Alex