ternary

问题 In JavaScript, rather than having to assign the result to a variable, is it possible to return the result of a ternary in one line of code? e.g. Instead of this: function getColor(val){ var result = val <= 20 ? '#000' : val >= 80 ? '#999' : '#555'; return result; } Can we do something like this... function getColor(val){ return val <= 20 ? '#000' : val >= 80 ? '#999' : '#555'; } I am asking this because I just tried the above and nothing was returned. 回答1: Yes. It's possible. Also you can

问题 I'm trying to work out how I can use multiple conditions with ternary operator in D3 (still finding my way with D3). I have a spreadsheet with a column legislative and the values included are Yes1, Yes2, Yes3 and No. For Yes1 I want to color my circles red, Yes2 are pink, Yes3 are orange and No are grey. The code below colors all circles either red or pink only. .style("fill", function(d) { return (d.data.legislative == "Yes1" ? "red" : "grey" || "Yes2" ? "pink" : "grey" || "Yes3" ? "orange"

问题 Assume I have a list of binary parameters (in reality it is a list of checkboxes' IsChecked.Value property). I'm trying to get the bool? (ternary) result that: is true if all the elements in the list are true is false if all the elements in the list are false is null in all other cases, thus there are both true and false elements in the list or the list is empty Until now I came up with the solution that requires iterating over the list twice (checking whether all elements are either true or

问题 This is a working code: String a = "first"; String b = "second"; String object; System.out.println(object != null ? a : b); But it isn't: String a = "first"; String b = "second"; String object; object != null ? System.out.println(a) : System.out.println(b); Why? 回答1: A per the spec It is a compile-time error for either the second or the third operand expression to be an invocation of a void method. println is a method from the PrintStream class (which System.out is an instance of) and it has

问题 I want to evaluate a simple ternary operator inside of a string and can't seem to find the correct syntax. My code looks like this: foreach ($this->team_bumpbox as $index=>$member) echo ".... class='{((1) ? abc : def)}'>...."; but I can't seem to get it to work properly. Any ideas on how to implement this? 回答1: You can't do it inside the string, per se. You need to dot-concatenate. Something like this: echo ".... class='" . (1 ? "abc" : "def") . "'>...."; 来源： https://stackoverflow.com

问题 Im not quite sure how to read ternary relationships within a ER-Diagram. Lets say this is the ternary relationship that is given. What can I interpret out of that? It says that you have to put your hand on 2 entity sets and then read it like that. Hand on Account and User: A pair of Account and User can be associated with M projects. Hand on Account and Project: A pair of Account and Project can be associated with M users. Hand on Project and User: A pair of Project and User can be associated

问题 puts bool ? "true" : "false" is proper, but bool ? puts "true" : puts "false" is not. Can somebody explain to me why this is? Side note: bool ? ( puts "true" ) : ( puts "false" ) works fine as well. 回答1: When you don't put the parentheses on a method call, Ruby assumes you want everything to the end of the line to be the arguments. That is to say, these calls are equivalent (and invalid): bool ? puts "true" : puts "false" bool ? puts("true" : puts "false") 来源： https://stackoverflow.com

问题 I have a doubt in the following scenario (C++): Say, I have an if condition if ( a ? b ? c : d : false) { // do something } else { // do something else } This is my interpretation of how it works: If a is true, it checks b. Then, - If b is true, the if loop is reduced to if (c) - If b is false, the if loop is reduced to if (d) If a is false, the if loop is reduced to if (false) Is my understanding correct? Is using this better or multiple if / else checks? 回答1: Please use this in parenthesis,

问题 I use a paging system like this: <?php $p = $_GET['p']; switch($p) { case "start": $p = "pages/start.php"; $currentPageId = 1; break; case "customers": $p = "pages/customers.php"; $currentPageId = 2; break; default: $p = "pages/start.php"; $currentPageId = 1; break; } ?> I want to set css class="active" to the menu item of the page i'm on. It works if I print <li> items like this: <li><a href="?p=start" <?php if ($currentPageId == 1) {echo "class='active'";}else {} ?>>Start</a></li> But I

问题 So the operator precedence of the ternary operator in C seems truly bizarre to me. Case in point: #include <stdio.h> int main () { int i=5; int j=6; int k=7; printf("A: %d\n", i+j+(k!=7)?1:11); //prints 1 printf("B: %d\n", i+j+((k!=7)?1:11)); //prints 22 return 0; } This seems similar to the question here: C++ ternary conditional and assignment operator precedence Ternary operator evaluation order As a clarification, I understand that the parentheses make it work, as my comments in my