Why do some newer programming languages almost always have the var keyword and write the type after the variable, for example: var x int = 12345 var y: Int = 67890 I know that type inference can be implemented in this way, which can be written as foll...
java8 s Optional doesn t make the program concise, so don t talk about him. Okay, thank you . after looking at the following question, I think this design is very good can null.method () in Java be designed to return null? now the version ...
for example, wouldn t it be better to configure it uniformly in the properties file? ...
there seem to be only six data types in python3 (strings, numbers, lists, dictionaries, tuples, collections), but I recently learned about the chapter on classes. 1 is an "instance " generated by class instantiation a data type? 2 are binary arrays an...
redis uses the setnx command to create locks. How long should I set the expiration time? How to set the failure time is too short, the method is not finished, the lock is automatically released, then concurrency problems will arise. If you set it for too...
< H2 > question < H2 > want to customize the preview style of markdown on vscode. The official solution is to add the following code to the settings: The same problem was found in Issues , but the official solution is invalid. Unfortunately, the ...
def test(def_arg=None): if def_arg == None: def_arg = [] def_arg.append(1) return def_arg test() test() when the test function is called for the first time, def_arg is assigned to the value of none when the function is defined, so d...
what s wrong with not adding this class? Ask for advice ...
how to write the condition that sphinx is not equal to, such as id! = 123 ...