From a technical standpoint, all three versions are equivalent. That being said, my rule of thumb for styles is that if you can read it as if it was English (read | as “when”, | otherwise as “otherwise” and = as “is” or “be”), you’re probably doing something right. if..then..else is for when you have … Read more
My initial reaction was #ifdef, of course, but I think #if actually has some significant advantages for this – here’s why: First, you can use DEBUG_ENABLED in preprocessor and compiled tests. Example – Often, I want longer timeouts when debug is enabled, so using #if, I can write this DoSomethingSlowWithTimeout(DEBUG_ENABLED? 5000 : 1000); … instead … Read more
I would use .change() and this.checked: $(‘#checkbox’).change(function(){ var c = this.checked ? ‘#f00’ : ‘#09f’; $(‘p’).css(‘color’, c); }); — On using this.checked Andy E has done a great write-up on how we tend to overuse jQuery: Utilizing the awesome power of jQuery to access properties of an element. The article specifically treats the use of … Read more
Yes, this is supposed to work. The case labels for a switch statement in C are almost exactly like goto labels (with some caveats about how they work with nested switch statements). In particular, they do not themselves define blocks for the statements you think of as being “inside the case”, and you can use … Read more
You got the order wrong. The if should be after the for (unless it is in an if-else ternary operator) [y for y in a if y not in b] This would work however: [y if y not in b else other_value for y in a]
Instead of COALESCE(a.addressid,0) AS addressexists, use CASE: CASE WHEN a.addressid IS NOT NULL THEN 1 ELSE 0 END AS addressexists or the simpler: (a.addressid IS NOT NULL) AS addressexists This works because TRUE is displayed as 1 in MySQL and FALSE as 0.
[[ $var =~ ^-?[0-9]+$ ]] The ^ indicates the beginning of the input pattern The – is a literal “-“ The ? means “0 or 1 of the preceding (-)” The + means “1 or more of the preceding ([0-9])” The $ indicates the end of the input pattern So the regex matches an optional … Read more
Use std::exchange: if (static bool do_once = true; std::exchange(do_once, false)) You can make it shorter reversing the truth value: if (static bool do_once; !std::exchange(do_once, true)) But if you are using this a lot, don’t be fancy and create a wrapper instead: struct Once { bool b = true; explicit operator bool() { return std::exchange(b, false); … Read more
There are a couple of important things to know about bash’s [[ ]] construction. The first: Word splitting and pathname expansion are not performed on the words between the [[ and ]]; tilde expansion, parameter and variable expansion, arithmetic expansion, command substitution, process substitution, and quote removal are performed. The second thing: An additional binary … Read more
One reliable way I use is: if($(“#checkSurfaceEnvironment-1”).prop(‘checked’) == true){ //do something } If you want to iterate over checked elements use the parent element $(“#parentId”).find(“checkbox”).each(function(){ if ($(this).prop(‘checked’)==true){ //do something } }); More info: This works well because all checkboxes have a property checked which stores the actual state of the checkbox. If you wish you … Read more