An if statement runs its else clause if its condition evaluates to false. Identically, a while loop runs the else clause if its condition evaluates to false. This rule matches the behavior you described: In normal execution, the while loop repeatedly runs until the condition evaluates to false, and therefore naturally exiting the loop runs … Read more
Interesting that the interview question asks about the advantages, without asking about disadvantages, for there are are both. Streams are a more declarative style. Or a more expressive style. It may be considered better to declare your intent in code, than to describe how it’s done: return people .filter( p -> p.age() < 19) .collect(toList()); … Read more
You can do: foreach ($arr as $key => $value) { echo $key; } As described in PHP docs.
Two simple solutions: Execute your code once before the while loop actions() { check_if_file_present # Do other stuff } actions #1st execution while [ current_time <= $cutoff ]; do actions # Loop execution done Or: while : ; do actions [[ current_time <= $cutoff ]] || break done
In addition, use collections.Counter to refactor your code: from collections import Counter words = [‘a’, ‘b’, ‘c’, ‘a’] Counter(words).keys() # equals to list(set(words)) Counter(words).values() # counts the elements’ frequency Output: [‘a’, ‘c’, ‘b’] [2, 1, 1]
You should better verify where you get that list from. An empty list is all you need, because an empty list won’t fail. If you get this list from somewhere else and don’t know if it is ok or not you could create a utility method and use it like this: for( Object o : … Read more
There is one important, and useful, distinction between the two. Because .ForEach uses a for loop to iterate the collection, this is valid (edit: prior to .net 4.5 – the implementation changed and they both throw): someList.ForEach(x => { if(x.RemoveMe) someList.Remove(x); }); whereas foreach uses an enumerator, so this is not valid: foreach(var item in … Read more
Biggest problem and root of ineffectiveness is indexing data.frame, I mean all this lines where you use temp[,]. Try to avoid this as much as possible. I took your function, change indexing and here version_A dayloop2_A <- function(temp){ res <- numeric(nrow(temp)) for (i in 1:nrow(temp)){ res[i] <- i if (i > 1) { if ((temp[i,6] … Read more
PERFORMANCE: There is absolutely no performance difference in where the try/catch structures are placed. Internally, they are implemented as a code-range table in a structure that is created when the method is called. While the method is executing, the try/catch structures are completely out of the picture unless a throw occurs, then the location of … Read more
Try: tourists.removeAll(Collections.singleton(null)); Read the Java API. The code will throw java.lang.UnsupportedOperationException for immutable lists (such as created with Arrays.asList); see this answer for more details.