boolean

问题 This question already has answers here : What values can appear in the “selected” attribute of the “option” tag? (8 answers) Closed 5 years ago . I've been reading some articles about HTML, XHTML, etc. In most of them (i.e. My preferred syntax style) say that boolean attributes should be written without any value, like this: <input type="text" required> They even say that it is wrong to use this attributes like this: <input type="text" required="required"> Some of this articles link W3 which

问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 3 years ago . I am getting an error using while loop in this manner, and I don't understand why: int count = 5; while(count--) //here showing an error { Console.WriteLine("Number : {0}", count); } However, in C, the code works properly. I am little bit confused about why I am getting this error. Can anyone explain why? 回答1: C

问题 public boolean checkGold(final int gold){ mRef.addListenerForSingleValueEvent(new ValueEventListener() { @Override public void onDataChange(DataSnapshot dataSnapshot) { String value = dataSnapshot.getValue(String.class); goldparse = Integer.parseInt(value); if (gold > goldparse){ /*Return*/ } } @Override public void onCancelled(FirebaseError firebaseError) { } }); return false; } I have method to check gold in outside but how to return false in method onDataChange . Thanks. 回答1: Firebase

问题 public boolean checkGold(final int gold){ mRef.addListenerForSingleValueEvent(new ValueEventListener() { @Override public void onDataChange(DataSnapshot dataSnapshot) { String value = dataSnapshot.getValue(String.class); goldparse = Integer.parseInt(value); if (gold > goldparse){ /*Return*/ } } @Override public void onCancelled(FirebaseError firebaseError) { } }); return false; } I have method to check gold in outside but how to return false in method onDataChange . Thanks. 回答1: Firebase

问题 Is there an easy way to convert an array of boolean values into 8-bit hexadecimal equivlents? For example, if I have bool[] BoolArray = new bool[] { true,false,true,true,false,false,false,true }; If true values=1 and false values=0 then I'd like a method or function that would convert the above array to 0xB1 (10110001). Does there exist such a function or method to do this? I am using C#, by the way. 回答1: Yes, you can use the BitArray class. Something like this should do it: BitArray arr =

问题 Anyone know an elegant way to return an array of index values from an array of Bools where the values are true. E.g: let boolArray = [true, true, false, true] This should return: [0,1,3] 回答1: let boolArray = [true, true, false, true] let trueIdxs = boolArray.enumerate().flatMap { $1 ? $0 : nil } print(trueIdxs) // [0, 1, 3] Alternatively (possibly more readable) let boolArray = [true, true, false, true] let trueIdxs = boolArray.enumerate().filter { $1 }.map { $0.0 } print(trueIdxs) // [0, 1,

问题 Alright so for this problem I am meant to be writing a function that returns True if a given string contains only characters from another given string. So if I input "bird" as the first string and "irbd" as the second, it would return True, but if I used "birds" as the first string and "irdb" as the second it would return False. My code so far looks like this: def only_uses_letters_from(string1,string2): """Takes two strings and returns true if the first string only contains characters also

问题 I have a jQuery function tied to my submit button like this: $(function () { $('#signupform').submit(function () { alert('test'); }); }); However, it fires whether or not the form is valid. My model is decorated with various DataAnnotations and the client-side validation is working well, but I only want that jQuery function to fire if the form has been validated. How do I accomplish that? EDIT: To clarify, I'm using MVC DataAnnotations + jQuery's unobtrusive javascript to handle the client

问题 I have a jQuery function tied to my submit button like this: $(function () { $('#signupform').submit(function () { alert('test'); }); }); However, it fires whether or not the form is valid. My model is decorated with various DataAnnotations and the client-side validation is working well, but I only want that jQuery function to fire if the form has been validated. How do I accomplish that? EDIT: To clarify, I'm using MVC DataAnnotations + jQuery's unobtrusive javascript to handle the client

问题 Since ANSI C99 there is _Bool or bool via stdbool.h . But is there also a printf format specifier for bool? I mean something like in that pseudo code: bool x = true; printf("%B\n", x); which would print: true 回答1: There isn't. But since any integral type shorter than int is promoted to int when passed down to printf() s variadic arguments, you can use %d : bool x = true; printf("%d\n", x); // prints 1 But why not printf(x ? "true" : "false"); or better printf("%s", x ? "true" : "false"); or