(update) Actually – there is one scenario where the for construct is more efficient; looping on an array. The compiler/JIT has optimisations for this scenario as long as you use arr.Length in the condition: for(int i = 0 ; i < arr.Length ; i++) { Console.WriteLine(arr[i]); // skips bounds check } In this very specific … Read more
Starting Python 3.8, and the introduction of assignment expressions (PEP 572) (:= operator), it’s now possible to capture an expression value (here sys.stdin.read(1)) as a variable in order to use it within the body of while: while (i := sys.stdin.read(1)) != ‘\n’: do_smthg(i) This: Assigns sys.stdin.read(1) to a variable i Compares i to \n If … Read more
Try this: import time t_end = time.time() + 60 * 15 while time.time() < t_end: # do whatever you do This will run for 15 min x 60 s = 900 seconds. Function time.time returns the current time in seconds since 1st Jan 1970. The value is in floating point, so you can even use … Read more
It’s not that different in bash. workdone=0 while : ; do … if [ “$workdone” -ne 0 ]; then break fi done : is the no-op command; its exit status is always 0, so the loop runs until workdone is given a non-zero value. There are many ways you could set and test the value … Read more
Declare MAX before you start the while loop. The way you have it you can only access within the while. Double MAX = 0; while (Condition) { MAX = somecode….. ….. } Console.WriteLine(“The OPTIMAL Value : ” + MAX);
First of all, ^Z or ^D are control characters that mean something to the terminal you are using, and sometimes that means for the terminal to signal end-of-file condition. Anyway, your three keypresses are processed by the terminal to take the following actions, after entering text: Flush the input (i.e. send the characters that have … Read more
If you run commands which read from stdin (such as ssh) inside a loop, you need to ensure that either: Your loop isn’t iterating over stdin Your command has had its stdin redirected: …otherwise, the command can consume input intended for the loop, causing it to end. The former: while read -u 5 -r hostname; … Read more
tkinter needs mainloop() to work correctly – it uses it to call all needed functions again and again – ie. to get key/mouse events from system, send them to widgets, updates values, and (re)draw widgets in window. In tkinter don’t use while True which runs forever (or runs longer time) because it blocks mainloop() in … Read more
You can use a do-while loop instead to eliminate the first input.nextInt(). int students = 0; do { try { // Get input System.out.print(“Enter the number of students: “); students = input.nextInt(); } catch (InputMismatchException e) { System.out.print(“Invalid number of students. “); } input.nextLine(); // clears the buffer } while (students <= 0); // Do … Read more
You could try to define the variable before the loop, e.g. $report = “”; while ($row = mysql_fetch_array($result)) { $report .= “a”.”b”.$row[“prevDOCid”]+1; } echo $report; I hope this helps you! Edit Use .= not +=