variable-assignment

问题 There is an error. Is it wrong to assign a value to a[i] in the following code? Or something is wrong with conditional operators? #include<stdio.h> #include<string.h> int main(){ char a[12]="sumit tyagi"; int i=0; while(a[i]!='\0'){ a[i]>90 ? a[i]=a[i]-32 : a[i]=a[i]+32; //error in this line i++; } printf("\n %s",a); 回答1: a[i]>90 ? a[i]=a[i]-32 : a[i]=a[i]+32; is not evaluated as a[i]>90 ? (a[i]=a[i]-32) : (a[i]=a[i]+32); since = has lower precedence than ?: . In standard C you can't write it

问题 According to the Python documentation on extended slices: If you have a mutable sequence such as a list or an array you can assign to or delete an extended slice, but there are some differences between assignment to extended and regular slices. Assignment to a regular slice can be used to change the length of the sequence: >>> a = range(3) >>> a [0, 1, 2] >>> a[1:3] = [4, 5, 6] >>> a [0, 4, 5, 6] Extended slices aren't this flexible. When assigning to an extended slice, the list on the right

问题 The basic example: var b = 10; var c = b; b++; console.log(b,c); >> 11 10 c looks like a copy of b . But in another case: var x = {}; var y = x; x.abc = 10; console.log(x.abc, y.abc); >> 10 10 Why is the y not a copy of x , but a reference which points to the same instance x points to? Also, I guessed b++ creates another instance, so b points to the new instance but c points to the old one. However... var u = 10; setTimeout(function() { console.log(u); }, 10000) u++; >> 11 If u++ creates a

问题 I have gone through these questions, Python assigning multiple variables to same value? list behavior concerned with tuples, I want just variables may be a string, integer or dictionary More elegant way of declaring multiple variables at the same time The question has something I want to ask, but the accepted answer is much complex so what I'm trying to achieve, I have this variables declared, and I want to reduce this declarations to as less line of code as possible. details = None product

问题 Most languages make it easy to take an array like [1, 2, 3] and assign those values to variables a , b , and c with a single command. For example, in Perl you can do ($a, $b, $c) = (1, 2, 3); What's the corresponding trick in PHP? [Thanks so much for the lightning fast answer! I know this is a trivial question but all the obvious google queries didn't turn up the answer so this is my attempt to fix that.] 回答1: Use list(): list($a, $b, $c) = $someArray; 回答2: Use list $arr = array(1,2,3); list(

问题 The new destructuring assignment features of ES6 are fairly well known now (live copy on Babel's REPL); in the case of variables that already exist: let a, b; // Existing variables let o = {a: "a", b: "b"}; // An object to get values from // ... ({a, b} = o); // Set them to the props from `o` console.log(a); // "a" console.log(b); // "b" Is there a simple converse in ES6? Setting properties on an existing object based on variables with the same name? (Other than the obvious o.a = a; o.b = b;

问题 I see a article about the immutable object. It says when: variable = immutable As assign the immutable to a variable. for example a = b # b is a immutable It says in this case a refers to a copy of b , not reference to b . If b is mutable , the a wiil be a reference to b so: a = 10 b = a a =20 print (b) #b still is 10 but in this case: a = 10 b = 10 a is b # return True print id(10) print id(a) print id(b) # id(a) == id(b) == id(10) if a is the copy of 10 , and b is also the copy of 10 , why

问题 I have code in my C++ application that generally does this: bool myFlag = false; while (/*some finite condition unrelated to myFlag*/) { if (...) { // statements, unrelated to myFlag } else { // set myFlag to true, perhaps only if it was false before? } } if (myFlag) { // Do something... } The question I have pertains to the else statement of my code. Basically, my loop may set the value of myFlag from false to true, based on a certain condition not being met. Never will the flag be unset

问题 How can I assign the same value for multiple variables in PHP at once ? I have something like: $var_a = 'A'; $var_b = 'A'; $same_var = 'A'; $var_d = 'A'; $some_var ='A'; In my case, I can't rename all variables to have the same name (that would make things more easy), so is there any way to assign the same value to all variables in a much more compact way? 回答1: $var_a = $var_b = $same_var = $var_d = $some_var = 'A'; 来源： https://stackoverflow.com/questions/11651594/assign-same-value-to

问题 I've asked a similar question on structs here but I'm trying to figure out how C handles things like assigning variables and why it isn't allowed to assign them to eachother if they are functionally the same. Lets say I have two arrays: int x[10]; int y[10]; Why won't x = y compile? If they are both the same "signature" like that, then shouldn't you be able to assign them back and forth? Can I declare these in a way that would allow me to do that in C? It makes sense to me that you would be