Generic iterator
Here are some articles you might find of interest Giving STL Iterators a Base Class Type Erasure for C++ Iterators any_iterator Class Reference
containers
Getting container/parent object from within python
Pass a reference to the Bar object, like so: class Foo(object): def __init__(self): self.text = “Hello World” # has to be created first, so Bar.__init__ can reference it self.bar = Bar(self) class Bar(object): def __init__(self, parent): self.parent = parent self.newText = parent.text foo = Foo() Edit: as pointed out by @thomleo, this can cause problems … Read more
How to check if a process is running inside docker container?
Docker creates .dockerenv and .dockerinit (removed in v1.11) files at the top of the container’s directory tree so you might want to check if those exist. Something like this should work. #!/bin/bash if [ -f /.dockerenv ]; then echo “I’m inside matrix ;(“; else echo “I’m living in real world!”; fi
How to define build-args in docker-compose?
You can specify the arguments directly in your docker-compose file: node1: build: context: node1 args: ADMIN_USERNNAME: weblogic1 ADMIN_PASSWORD: weblogic1 ADMIN_NAME: admin1 image: node1 container_name: node1 See a full example: MWE The official docs (legacy v3 here) have all detail.
Checking for NaN presence in a container
Question #1: why is NaN found in a container when it’s an identical object. From the documentation: For container types such as list, tuple, set, frozenset, dict, or collections.deque, the expression x in y is equivalent to any(x is e or x == e for e in y). This is precisely what I observe with … Read more
How do I mount a Docker volume while using a Windows host?
It is possible the / is interpreted as an option by the CMD Windows shell. Try first a docker-machine ssh default, in order to open an ssh session in your VM. From there try the docker run again: docker run -v /c/Users/phisch/dev/htdocs:/var/www phisch:dev As commented by thaJeztah in issue 18290: You could consider using docker-compose; … Read more
Is the behaviour of Python’s list += iterable documented anywhere?
From Guido van Rossum: It works the same way as .extend() except that it also returns self. I can’t find docs explaining this. 🙁 Here is the relevant source code taken from listobject.c: list_inplace_concat(PyListObject *self, PyObject *other) { PyObject *result; result = listextend(self, other); if (result == NULL) return result; Py_DECREF(result); Py_INCREF(self); return (PyObject *)self; … Read more
How can I use an array as map value?
You can’t copy arrays by value like that. Here are several solutions, but I recommend #4 for your needs: Use an std::vector instead of an array. Use a map of pointers to arrays of 3 elements: int red[3] = {1,0,0}; int green[3] = {0,1,0}; int blue[3] = {0,0,1}; std::map<int,int(*)[3]> colours; colours.insert(std::pair<int,int(*)[3]>(GLUT_LEFT_BUTTON,&red)); colours.insert(std::pair<int,int(*)[3]>(GLUT_MIDDLE_BUTTON,&blue)); colours.insert(std::pair<int,int(*)[3]>(GLUT_RIGHT_BUTTON,&green)); // Watch … Read more
Why does storing references (not pointers) in containers in C++ not work?
Containers store objects. References are not objects. The C++11 specification clearly states (§23.2.1[container.requirements.general]/1): Containers are objects that store other objects.
Template class with template container
You should use template template parameters: template<typename T, template <typename, typename> class Container> // ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ class MyMultibyteString { Container<T, std::allocator<T>> buffer; // … }; This would allow you to write: MyMultibyteString<int, std::vector> mbs; Here is a compiling live example. An alternative way of writing the above could be: template<typename T, template <typename, typename = std::allocator<T>> … Read more