Based on the other answers, I think the cleanest solutions are #Handles None return from get_list for item in get_list() or []: pass #do something or the comprehension equiv result = [item*item for item in get_list() or []]
Java 8 (2014) has added IntStream (similar to apache commons IntRange), so you don’t need external lib now. import java.util.stream.IntStream; IntStream.range(0, 3).forEachOrdered(n -> { System.out.println(n); }); forEach can be used in place of forEachOrdered too if order is not important. IntStream.range(0, 3).parallel() can be used for loops to run in parallel
No, you can’t use yield inside of the inner function. But in your case you don’t need it. You can always use for-of loop instead of forEach method. It will look much prettier, and you can use continue, break, yield inside it: var trivialGenerator = function *(array) { for (var item of array) { // … Read more
The answer the majority of the time is it does not matter. The number of items in the loop (even what one might consider a “large” number of items, say in the thousands) isn’t going to have an impact on the code. Of course, if you identify this as a bottleneck in your situation, by … Read more
The short form is as follows (called dict comprehension, as analogy to the list comprehension, set comprehension etc.): x = { row.SITE_NAME : row.LOOKUP_TABLE for row in cursor } so in general given some _container with some kind of elements and a function _value which for a given element returns the value that you want … Read more
In general, the fewer times you hit the database, the better. There are a number of reasons for this, including: The database will be able to optimize better if it can try to fetch everything all at once You remove all of the overhead of communicating with the database multiple times, which can be quite … Read more
One approach is using Array.prototype.entries(): for (const [i, value] of arr.entries()) { if (i === arr.length – 1) { // do your thing } } Another way is keeping a count outside the loop like Shidersz suggested. I don’t think you want to check indexOf(item) though because that poses a problem if the last item … Read more
From C++1z/17, you can use structured bindings: #include <iostream> #include <map> #include <string> int main() { std::map<int, std::string> m; m[1] = “first”; m[2] = “second”; m[3] = “third”; for (const auto & [key, value] : m) std::cout << value << std::endl; }
Yes. It uses the same syntax as lifetimes. fn main() { ‘outer: for x in 0..5 { ‘inner: for y in 0..5 { println!(“{},{}”, x, y); if y == 3 { break ‘outer; } } } } See loop labels documentation and the related section of the reference.