variables

问题 There is a global variable called numbers. Function one calculates a random number and stores it in mynumber variable. var mynumber; function one (){ var mynumber = Math.floor(Math.random() * 6) + 1; } I need to use it in a separate function as belows. But an error says undefined - that means the value from function one is not updated. function two (){ alert(mynumber); } How to overcome this problem. Is there a way to update the mynumber global variable. 回答1: If you declare a variable with

问题 I use variable assignment with mysql and I found a strange behavior. See this query : SET @v1=0; SET @v2=0; SELECT @v1, @v2 FROM MyTable table WHERE (@v1:=@v2) is not null AND (@v2:=2) is not null; I was thinking that conditions are parsed in this order : first (@v1:=@v2) is not null and after (@v2:=2) is not null and so the result must be : @v1 | @v2 --------- 0 | 2 But this is not the case. try this query and you will have: @v1 | @v2 --------- 2 | 2 Why ? 回答1: SQL is a declarative language,

问题 If you define my $top = (0 .. 100) you get each number 1,2,3,4...100 but how can I define $top to only produce 0, 2.5, 5, 7.5, ... 100? Thanks 回答1: @top = map { 2.5 * $_ } 0 .. 40; 回答2: #!/usr/bin/perl -w use strict; use warnings; use Data::Dumper; my @numbers = ( 0 .. 40 ); my @top = map { $_ * 5 / 2 } @numbers; print Dumper \@top; Output: $ ./test.pl $VAR1 = [ '0', '2.5', '5', '7.5', ... '95', '97.5', '100' ]; 来源： https://stackoverflow.com/questions/6783837/perl-defining-a-pattern-for-a

问题 I'm trying to pass a variable z = 100 from C++ to Matlab for further processing (this is just a very simplified example). I basically want this to be passed as a global variable such that I can access this variable from any Matlab function, (perhaps sent to the Matlab Workspace). Here is my C++ code (I'm using the Matlab engine from within C++): #include "opencv2/highgui/highgui.hpp" #include "opencv2/opencv.hpp" #include <iostream> #include <math.h> #include <fstream> #include <stdio.h>

问题 I am trying to automate file upload in two browsers but the window name is "File Upload" in Firefox and "Open" in Chrome. I don't want to write two different scripts. How to choose title- and file name at runtime to achieve cross browser compatibility? I use Selenium and testNG, AutoIt only for file upload. 回答1: Set a variable based off the web browser being used, then use that variable. The code below should get you on the right track. $FirefoxUpload = "File upload" $ChromeUpload = "Open" if

问题 I employed the answer Marc B suggested and still got nothing in the variable when I echo'd it after the while loop, so I added a few checks to show status of things as they were processed through the code. When the if/else statement runs next, it shows the result that there is length to the variable. The next if/else statement branches to the else statement and then takes the else statement in the next if/else saying the xpath found nothing. So obviously when I go to use the variable $BEmp3s,

问题 I employed the answer Marc B suggested and still got nothing in the variable when I echo'd it after the while loop, so I added a few checks to show status of things as they were processed through the code. When the if/else statement runs next, it shows the result that there is length to the variable. The next if/else statement branches to the else statement and then takes the else statement in the next if/else saying the xpath found nothing. So obviously when I go to use the variable $BEmp3s,

问题 I have an issue with the above plugin (WP Session Manager) where the session variables I set, are not always set. I know the PHP I'm using to set the variables is correct as they do work sometimes. But for example, I can have them working perfectly fine and echo'ed out to the screen as a test, then I 'logout' and blank all the variables by setting them to "", then log back in (and set them again) but they do not get echo'ed out this time, meaning they must not be set. I know one works for

问题 How to display selected checkbox? I tried but it didnt work <input type=checkbox value="Administrative"<?php echo ($industry_sector1a == 'Administrative' ? 'selected="selected"' : ''); ?>name="industry_sector1"> Administrative I use the below for drop down boxes . <option value="-1"<?php echo ($native_language == '-1' ? 'selected="selected"' : ''); ?>>----- Please Select -----</option> <option value="1"<?php echo ($native_language == '1' ? 'selected="selected"' : ''); ?>>English - United

问题 I am trying to use a variable from a method I created in another class in the main section. For example: public class test { public static int n; public void getLower(){ int p = 12; } public static void main(String[] args) { test example = new test(); example.getLower(); System.out.println(p); } } However, I get the error message 'p cannot be resolved to a variable'. Is what I'm trying to do possible? Thanks in advance! 回答1: p is a local variable within the getLower method. You're not