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问题 I have seen How to suppress "error TS2533: Object is possibly 'null' or 'undefined'"?. And other things. This is not a duplicate! There are like 3 different ways to suppress this error. I do not want what. I do not want to disable strict null types either. I want a proper solution to code this properly. Can I create a new type that is the same as HTMLElement and Element just without null? What will happen at run-time if they are actually null and I just suppress the warning in TS. It feels

问题 When I used this code WHEN col1 NOT IN (SELECT col2 FROM table_name) THEN 'something' it didn't give the expected results knowing that col2 contains a NULL value, Why did this happened ? Does using IN with NULL values messes with data stored in memory or what? 回答1: This is not an issue with Oracle. This is how SQL is defined. When the subquery returns a NULL value with NOT IN , then no rows match at all. For this reason, I strongly recommend always using NOT EXISTS instead: WHEN NOT EXISTS

问题 I am using Azure pipelines variables to construct a set of parameters for a command. The type of variable I must use for Azure pipelines is in macro format (like $(var) ), you can see the details of it here: https://docs.microsoft.com/en-us/azure/devops/pipelines/process/variables?view=azure-devops&tabs=yaml%2Cbatch#runtime-expression-syntax If $(var) does not contain a value, instead of printing "nothing", it will print $(var) When I run my command and that value isn't passed in, an error

问题 I have a mysql procedure where I'm setting values using subqueries as it progresses, and partway through the subqueries, all structured the same only using different parameters, start returning null. If I literally copy and paste the subquery into a sql window, it returns a result. Service Revenue to Income Summary works just fine, but after "COGS to Income Summary", "VALUE" continues to return NULL DELIMITER $$ CREATE DEFINER=`shopf740`@`localhost` PROCEDURE `PeriodEnd`(IN `processdate` DATE

问题 I am trying to remove the null elements from the old 2d array and put it in a new 2d array, but the new 2d array is outputting all null elements. String[][] status = new String[P][M]; String[][] newStatus = new String[P][M]; for (int i = 0; i < status.length; i++) { for (int j = 0; j < status.length; j++) { if (status[i][j] != null) { newStatus[i][j] = status[i][j]; } } } Original 2d array: [[O, X, null, O, O, null, null], [null, null, O, null, null, O, O]] I want it to look like this: [[O, X

问题 Code below will raise a runtime error when append reflect.Value of nil : package main import ( "fmt" "reflect" ) func main() { var list []interface{} v := reflect.ValueOf(list) v = reflect.Append(v, reflect.ValueOf(1)) // [1] v = reflect.Append(v, reflect.ValueOf("1")) // [1, 1] v = reflect.Append(v, reflect.ValueOf(nil)) // runtime error fmt.Println(v) } So why there is a runtime error? how can I use reflect.Append to add a nil to interface{} slice? 回答1: interface{} is an interface type, and

问题 Code below will raise a runtime error when append reflect.Value of nil : package main import ( "fmt" "reflect" ) func main() { var list []interface{} v := reflect.ValueOf(list) v = reflect.Append(v, reflect.ValueOf(1)) // [1] v = reflect.Append(v, reflect.ValueOf("1")) // [1, 1] v = reflect.Append(v, reflect.ValueOf(nil)) // runtime error fmt.Println(v) } So why there is a runtime error? how can I use reflect.Append to add a nil to interface{} slice? 回答1: interface{} is an interface type, and

问题 The consensus of stackoverflow questions say that it is undefined behaviour. However, I recently saw a 2016 talk by Charles Bay titled: Instruction Reordering Everywhere: The C++ 'As-If" Rule and the Role of Sequence. At 37:53 he shows the following: C++ Terms Undefined Behaviour: Lack of Constraints (order of globals initialization) Unspecified Behaviour: Constraint Violation (dereferencing NULL pointer) Now I have conflicting information. Was this a typo? Has anything changed? 回答1: The

问题 I'm developing a PATCH API. If the fields are sent as JSON null value I need to save them as null . However I can't distinguish if they're sent as null or never sent. { "max_amount": null } Double maxAmount; I have Double , Integer , Date etc. fields. I can deserialize them to Double.NAN , Integer.MIN_VALUE when they're really sent as null to understand if they're sent as null . But Deserializers don't work when the field is null . Of course it's an option to send "-1" or an impossible value

问题 This is essentially a rehashing of the content of my answer here. I came across some weird behaviour when trying to solve this question, using pd.notnull . Consider x = ('A4', nan) I want to check which of these items are null. Using np.isnan directly will throw a TypeError (but I've figured out how to solve that). Using pd.notnull does not work. >>> pd.notnull(x) True It treats the tuple as a single value (rather than an iterable of values). Furthermore, converting this to a list and then