What’s a generator? To understand what a generator is, we need to first look at what is a build system. CMake doesn’t compile or link any source files. It used a generator to create configuration files for a build system. The build system uses those files to compile and link source code files. So what’s … Read more
def getPermutations(string, prefix=””): if len(string) == 1: yield prefix + string else: for i in xrange(len(string)): for perm in getPermutations(string[:i] + string[i+1:], prefix+string[i]): yield perm Or without an accumulator: def getPermutations(string): if len(string) == 1: yield string else: for i in xrange(len(string)): for perm in getPermutations(string[:i] + string[i+1:]): yield string[i] + perm
You can return a tuple of record and exception in the parsefunc and let the consumer function decide what to do with the exception: import random def get_record(line): num = random.randint(0, 3) if num == 3: raise Exception(“3 means danger”) return line def parsefunc(stream): for line in stream: try: rec = get_record(line) except Exception as … Read more
sum takes an iterable of things to add up, while print takes separate arguments to print. If you want to feed all the generator’s items to print separately, use * notation: print(*(i for i in range(1, 101))) You don’t actually need the generator in either case, though: sum(range(1, 101)) print(*range(1, 101)) If you want them … Read more
When a generator throws an exception, it exits. You can’t continue consuming the items it generates. Example: >>> def f(): … yield 1 … raise Exception … yield 2 … >>> g = f() >>> next(g) 1 >>> next(g) Traceback (most recent call last): File “<stdin>”, line 1, in <module> File “<stdin>”, line 3, in … Read more
You can think of the value attribute of StopIteration (and arguably StopIteration itself) as implementation details, not designed to be used in “normal” code. Have a look at PEP 380 that specifies the yield from feature of Python 3.3: It discusses that some alternatives of using StopIteration to carry the return value where considered. Since … Read more
We talked about this in the TC39 face-to-face meetings and it is deliberate that we don’t expose a way to detect whether a function is a generator or not. The reason is that any function can return an iterable object so it does not matter if it is a function or a generator function. var … Read more
As pointed in the comments, you could do it in a new thread, using Queue. The drawback is that you’d still need some way to access the final result (what fmin returns at the end). My example below uses an optional callback to do something with it (another option would be to just yield it … Read more
Generators exist in C++, just under another name: Input Iterators. For example, reading from std::cin is similar to having a generator of char. You simply need to understand what a generator does: there is a blob of data: the local variables define a state there is an init method there is a “next” method there … Read more
If you want to add some custom field to your registration process because your are using official laravel auth you can add your fields in : /resources/views/auth/register.blade.php and then you can validate and save your inputs in : /app/Http/Controllers/Auth/RegisterController.php you don’t need to add anything to registeruser in vendor because every thing you add will … Read more