variable-assignment

问题 im working on a assignment where I now have to implement the Try & Catch-method too catch inputs other than numbers in my program. I understand the process and explanations in my study-book and have also done some minor examples while trying it out. But when I want to implement this into my assignment I am getting stuck. Can someone please explain to me in a manor as to not spoil anything but try and help me along the way? Here is my code: using System; namespace BastunKP { class Program {

问题 im working on a assignment where I now have to implement the Try & Catch-method too catch inputs other than numbers in my program. I understand the process and explanations in my study-book and have also done some minor examples while trying it out. But when I want to implement this into my assignment I am getting stuck. Can someone please explain to me in a manor as to not spoil anything but try and help me along the way? Here is my code: using System; namespace BastunKP { class Program {

问题 im working on a assignment where I now have to implement the Try & Catch-method too catch inputs other than numbers in my program. I understand the process and explanations in my study-book and have also done some minor examples while trying it out. But when I want to implement this into my assignment I am getting stuck. Can someone please explain to me in a manor as to not spoil anything but try and help me along the way? Here is my code: using System; namespace BastunKP { class Program {

问题 I've used this function so many times but only now thought 'why does it work?'. How can R's colnames() function assign new column names to a data frame? I mean I get how colnames(df) will return the column names of a data frame. But how can it also assign new ones? aa <- mtcars colnames(aa) colnames(aa) <- LETTERS[1:ncol(aa)] colnames(aa) # ^ how can colnames function either return column names or assign new ones? It's just a function. # but we can't change the number of columns this way:

问题 The program available on The Go Playground reads package main import "fmt" func main() { var name string = nil fmt.Println(name) } and yields an error prog.go:6: cannot use nil as type string in assignment I understand "" is the "zero value" for strings. I don't understand why I cannot assign nil to my string . 回答1: The simple answer is that nil is not defined to be a valid value for type string in the language specification. ...but maybe you want a longer answer? nil is the zero value for

问题 The program available on The Go Playground reads package main import "fmt" func main() { var name string = nil fmt.Println(name) } and yields an error prog.go:6: cannot use nil as type string in assignment I understand "" is the "zero value" for strings. I don't understand why I cannot assign nil to my string . 回答1: The simple answer is that nil is not defined to be a valid value for type string in the language specification. ...but maybe you want a longer answer? nil is the zero value for

问题 This question already has answers here : Generator expression uses list assigned after the generator's creation (5 answers) Closed 12 months ago . I was running a piece of code that unexpectedly gave a logic error at one part of the program. When investigating the section, I created a test file to test the set of statements being run and found out an unusual bug that seems very odd. I tested this simple code: array = [1, 2, 2, 4, 5] # Original array f = (x for x in array if array.count(x) ==

问题 Consider the following example: class Quirky { public static void main(String[] args) { int x = 1; int y = 3; System.out.println(x == (x = y)); // false x = 1; // reset System.out.println((x = y) == x); // true } } I'm not sure if there is an item in the Java Language Specification that dictates loading the previous value of a variable for comparison with the right side ( x = y ) which, by the order implied by brackets, should be calculated first. Why does the first expression evaluate to

问题 Consider the following code; it is a bad programming practice. I am wondering why the resulting list A is [1, 1, 3] rather than [1, 2, 1] . From the view of Java, the result should be [1, 2, 1] . Can anyone explain why this result is what it is? A = [1, 2, 3] t = 2 t = A[t] = A.count(3) After evaluation, A is [1, 1, 3] and t is 1 . My Python version is 3.3. 回答1: On line 3 you have a chained assignment t = A[t] = A.count(3) t = A.count(3) is evaluated first – t set to the return value of A

问题 Consider the following code; it is a bad programming practice. I am wondering why the resulting list A is [1, 1, 3] rather than [1, 2, 1] . From the view of Java, the result should be [1, 2, 1] . Can anyone explain why this result is what it is? A = [1, 2, 3] t = 2 t = A[t] = A.count(3) After evaluation, A is [1, 1, 3] and t is 1 . My Python version is 3.3. 回答1: On line 3 you have a chained assignment t = A[t] = A.count(3) t = A.count(3) is evaluated first – t set to the return value of A