while-loop

问题 In these benchmarks, http://jsperf.com/the-loops, Barbara Cassani showed that a "reverse while" loop is way faster, while (iterations > 0) { a = a + 1; a = a - 1; iterations--; } than a usual "for" loop: for (i = 0; i < iterations; i++) { a = a + 1; a = a - 1; } Why? Update Okay, forget about it, there is a bug in the test, iterations = 100 , is executed only once per page. Therefore reducing it, well, means that we don't really enter the loops. Sorry. 回答1: Except for the big bug in the

问题 Very simple example code (only for demonstration, no use at all): repeat { while (1 > 0) { for (i in seq(1, 100)) { break # usually tied to a condition } break } break } print("finished") I want to break out from multiple loops without using break in each loop separately. According to a similar question regarding python, wrapping my loops into a function seems to be a possible solution, i.e. using return() to break out of every loop in the function: nestedLoop <- function() { repeat { while

问题 I'm developing an appointment calendar application. Still newbie here. I need help in this area. I need to have a double looping in columns (`calendarID, Slot, AppointmentDate'). The 'slot' column will have a value of 1,2,3,4,5,6,7,8 upto 28 repeatedly while the calendarID will continuously loop to 868 value. The Appointment date will have the value from 1 Aug2013 to 31 Aug 2013 (actually I'm planning to do this for 1 whole year) expected result calendarID | Slot | AppointmentDate -----------

问题 so im trying to make the images change and make them into a loop and i came up with this script, and the problem i am having is that, when it change to the second picture the javascript would freeze up on me, I know it the while(true) part but i dont know how to fix it, please help. thanks you var images = new Array(); images[0] = "image1.jpg"; images[1] = "image2.jpg"; images[2] = "image3.jpg"; setTimeout("changeImage()", 3000); var x=0; function changeImage() { while(true){ document

问题 I'm a PHP programmer doing some BASH scripting and I'm not sure how global variables are working. I want to increment the 3 variables for each line in a supplied file. However, when I get to the bottom, the variables are still set at 0. How do I access the variables that are incremented within the WHILE DO loop? I just want to echo them out at the end.. From what I understand we're in kornshell #!/bin/bash typeset -i i=0 typeset -i t1=0 typeset -i t2=0 sed 1d $1 | \ while read word1 word2

问题 I need a user to enter a number and enter out the closest prime number to the value they put in. I am struggling on how to check the prime numbers before and after the number they put in. The last part is to print the smaller value of the two prime numbers if they are the same distance away from the inputted number. n = int(input("Enter n: ")) holder1 = n holder2 = n prime = True holder3 = 0 holder4 = 0 for i in range(2,n): if (n % i) == 0: prime = False if(prime == True): print("The prime

问题 Just started python and racking my brains on this but can't seem to get it right. print('Enter correct username and password combo to continue') count=0 password=Hytu76E username=bank_admin while password!='Hytu76E' and username!='bank_admin' and count<4: username=input('Enter username: ') and password=input('Enter password: ') if password=='Hytu76E' and username=='bank_admin': print('Access granted') else: print('Access denied. Try again.') count-=1 syntax error, can't assign to operator on

问题 I want to be able to loop my program over and over again, depending on the user input. Could you please look at my code below and help me to understand how this can be done... import java.util.*; public class Lab4 { public static void main(String[] args){ System.out.println("Body Fat Calculator"); double A1,A2,A3,A4,A5,B; //female double a1,a2,b; //male double bodyWeight,wristMeasurement,waistMeasurement,hipMeasurement,forearmMeasurement; //both double bodyFat,bodyFatpercent; //both Scanner

问题 This question already has answers here : How can I quickly sum all numbers in a file? (27 answers) Closed 3 years ago . How do I add numbers together inside the shell using a while or for loop? I just want a really simple program that works with standard input and files. Example: $ echo 1 2 | sh myprogram 3 And if a file myfile contains a list of numbers, I want to be able to do this: sh myprogram myfile and get the sum of the numbers as output. 回答1: While this question is at its core a

问题 I am having problems including multiple statements with while loop in python. It works perfectly fine with single condition but when i include multiple conditions, the loop does not terminate. Am i doing something wrong here? name = raw_input("Please enter a word in the sentence (enter . ! or ? to end.)") final = list() while (name != ".") or (name != "!") or (name != "?"): final.append(name) print "...currently:", " ".join(final) name = raw_input("Please enter a word in the sentence (enter .