Good lord no. Sometimes there is a possibility that something can occur in the loop that satisfies the overall requirement, without satisfying the logical loop condition. In that case, break is used, to stop you cycling around a loop pointlessly. Example String item; for(int x = 0; x < 10; x++) { // Linear search. … Read more
Use break: while (true) { …. if (obj == null) { break; } …. } However, if your code looks exactly like you have specified you can use a normal while loop and change the condition to obj != null: while (obj != null) { …. }
Sometimes it is helpful to have multiple cases associated with the same code block, such as case ‘A’: case ‘B’: case ‘C’: doSomething(); break; case ‘D’: case ‘E’: doSomethingElse(); break; etc. Just an example. In my experience, usually it is bad style to “fall through” and have multiple blocks of code execute for one case, … Read more
next inside a block returns from the block. break inside a block returns from the function that yielded to the block. For each this means that break exits the loop and next jumps to the next iteration of the loop (thus the names). You can return values with next value and break value.
You could use the stopifnot() function if you want the program to produce an error: foo <- function(x) { stopifnot(x > 500) # rest of program }
Basically to make it more familiar to C/C++/Java developers. Personally I think it was a mistake, but that’s the reasoning. I would have preferred a forced block: case ‘1’: { } Aside from anything else, that would have avoided the weird variable scoping situations for switch/case. You could still have multiple case labels, of course: … Read more
The easiest way is to just interrupt it with the usual Ctrl-C (SIGINT). try: while True: do_something() except KeyboardInterrupt: pass Since Ctrl-C causes KeyboardInterrupt to be raised, just catch it outside the loop and ignore it.
This can be nearly done by setting a new variable as a flag to break iterating: {% set break = false %} {% for post in posts if not break %} <h2>{{ post.heading }}</h2> {% if post.id == 10 %} {% set break = true %} {% endif %} {% endfor %} An uglier, but … Read more
You can turn warnings into errors with: options(warn=2) Unlike warnings, errors will interrupt the loop. Nicely, R will also report to you that these particular errors were converted from warnings. j <- function() { for (i in 1:3) { cat(i, “\n”) as.numeric(c(“1”, “NA”)) }} # warn = 0 (default) — warnings as warnings! j() # … Read more
It’s fine, the continue statement relates to the enclosing loop, and your code should be equivalent to (avoiding such jump statements): while (something = get_something()) { if (something == A || something == B) do_something(); } But if you expect break to exit the loop, as your comment suggest (it always tries again with another … Read more