static-variables

问题 I have a problem inside a pyspark udf function and I want to print the number of the row generating the problem. I tried to count the rows using the equivalent of "static variable" in Python so that when the udf is called with a new row, a counter is incremented. However, it is not working: import pyspark.sql.functions as F def myF(input): myF.lineNumber += 1 if (somethingBad): print(myF.lineNumber) return res myF.lineNumber = 0 myF_udf = F.udf(myF, StringType()) How can I count the number of

问题 I know about the problem of the order of initialization of static variables from different translation units. However, my problem is within one translation unit and, in fact, within one struct: template <int size> struct SlidingTile { using AllActions = std::array<int, size>; using AllMDDeltas = std::array<int, size>; int mdDelta(int i) const { return mdDeltas_[i]; } static AllActions computeAllActions() { std::cout << "computeAllActions" << std::endl; AllActions res; for (int i = 0; i < size

问题 This question already has answers here : Closed 7 years ago . Possible Duplicate: The initialization of static variable in C I know that either global variables or static are automatically initialized with zero in C. However, I'm not sure if both or only one of them are initialized. Note that I'm not talking about variables defined in functions but globally in the .c file. So which of the following variables are automatically initialized with zero? static struct mystruct var1; struct mystruct

问题 Are the following two static variable declarations equivalent? 1. static int var1; static int var2; static int var3; 2. static int var1, var2, var3; More specifically, in case 2, will all variables be static , or just var1 ? 回答1: Yes the declarations in case 1 and 2 are identical. We can see this by going to the draft C99 standard section 6.7.5 Declarators which says ( emphasis mine going forward ): Each declarator declares one identifier, and asserts that when an operand of the same form as

问题 In PHP, What is is the difference between: Constants and static variables? Extending a class and creating its object? I know how they can be used, but I can't clearly distinguish between them. 回答1: Static is for: class properties or methods as static makes them accessible without needing an instantiation of the class So, the value returned by a static member may differ. For example, you can call a static method with different result depending of what parameters you pass to it. Constants value

问题 This question already has answers here : How to avoid having class data shared among instances? (7 answers) Closed 4 years ago . I'm new to Python, with more of a Java background. I understand the concept of static class variables in Python, but it's come to my attention that lists and objects don't work the same way a string would, for example - they're shared between instances of a class. In other words: class box (): name = '' contents = [] def __init__ (self, name): self.name = name def

问题 I have a bankAccount object I'd like to increment using the constructor. The objective is to have it increment with every new object the class instantiates. Note: I've overriden the ToString() to display the accountType and accountNumber; Here is my code: public class SavingsAccount { private static int accountNumber = 1000; private bool active; private decimal balance; public SavingsAccount(bool active, decimal balance, string accountType) { accountNumber++; this.active = active; this

问题 I am attempting to add a variable to a class that holds instances to the class. The following is a shortened version of my code. class Classy : def __init__(self) : self.hi = "HI!" # "CLASSIES" variable holds instances of class "Classy" CLASSIES = [] for i in xrange(0,4) : CLASSIES.append(Classy()) Upon running the code, I get the following error. Traceback (most recent call last): File "classy.py", line 6, in Classy CLASSIES.append(Classy()) NameError: name 'Classy' is not defined Is there

问题 This question already has answers here : Declaring static constants in ES6 classes? (9 answers) Closed 3 years ago . I have a JavaScript class following the ECMA6 standard, and I would like to create a static variable in it. To achieve this I read the following documentation: JavaScript Static keyword MDN Static variables in JavaScript The first link demonstrates how one can create static methods inside a class in ECMA 6, while the second link demonstrates how you can use prototype and

问题 I'm writing a simple android application which is basically a modification of the fragments demo available in the android documentation. In the app, there is a file called Ipsum.java which has a static ArrayList of Strings called Headlines. In the onCreate() method of the main activity, I have the following code which adds some elements into the array list. if (savedInstanceState == null){ Ipsum.Headlines.add("String 1 "); Ipsum.Headlines.add("String 2"); } savedInstanceState is a Bundle that