On Dec 12, 2019, at 20:51, Tim Peters <tim.peters@gmail.com> wrote:
BTW, you can go a long way in Python without knowing anything about `iter()` or `next()`. But not without mastering `for` loops. That's why I prefer to say that, for ordinary cases,
a = first(it)
has the same effect as:
for a in it: break
I just had to explain to someone today that a loop like this doesn’t just use up and throw away a value from it, but leaves a bound to that first value. Admittedly, this wasn't a novice, but a pretty experienced C++ and Java developer who doesn’t do much Python, who just didn’t know that Python scopes are functions rather than all compound statements. That’s not a confusion a novice would have. But would a novice actually get that it is usefully assigning the first thing in it to a? It seems obvious to me, but I’m not sure it would to most people who don’t know enough Python to know about iter. For that matter, even if they do know this leaves a bound to something useful, do they know what it does with a set? If not, what have we solved here? And do we even really need to solve this problem How many novices are going to be confused about what first does with a set, and need to know the answer? Plus, if first really has to be this completely understandable to people who don’t know about iter, how can we put it in itertools, a module whose docs start off with a nice friendly introduction about the building blocks of an algebra for iterators that you can compose into powerful tools?