The object is added to the application or the project using the command Project ‣ Add object ‣ POU . In the Device tree or in the POUs view, function POUs have the suffix (FUN) .
Provides a mechanism for looking up an object associated with the current HTTP request.
The model that this view will display data for. Specifying model Foo is effectively the same as specifying queryset Foo.objects.all(), where objects stands for Foo`s default manager .
A QuerySet that represents the objects. If provided, the value of queryset supersedes the value provided for model.
This attribute can help mitigate insecure direct object reference attacks. When applications allow access to individual objects by a sequential primary key, an attacker could brute-force guess all URLs; thereby obtaining a list of all objects in the application. If users with access to individual objects should be prevented from obtaining this list, setting query_pk_and_slug to True will help prevent the guessing of URLs as each URL will require two correct, non-sequential arguments. Using a unique slug may serve the same purpose, but this scheme allows you to have non-unique slugs.
Returns the single object that this view will display. If queryset is provided, that queryset will be used as the source of objects; otherwise, get_queryset() will be used. get_object() looks for a pk_url_kwarg argument in the arguments to the view; if this argument is found, this method performs a primary-key based lookup using that value. If this argument is not found, it looks for a slug_url_kwarg argument, and performs a slug lookup using the slug_field.
Returns the queryset that will be used to retrieve the object that this view will display. By default, get_queryset() returns the value of the queryset attribute if it is set, otherwise it constructs a QuerySet by calling the all() method on the model attribute`s default manager.
Return the context variable name that will be used to contain the data that this view is manipulating. If context_object_name is not set, the context name will be constructed from the model_name of the model that the queryset is composed from. For example, the model Article would have context object named .
Returns context data for displaying the object.
Any variables from get_context_data() take precedence over context variables from context processors . For example, if your view sets the model attribute to User, the default context object name of user would override the user variable from the django.contrib.auth.context_processors.auth() context processor. Use get_context_object_name() to avoid a clash.
A mixin class that performs template-based response rendering for views that operate upon a single object instance. Requires that the view it is mixed with provides self.object, the object instance that the view is operating on. self.object will usually be, but is not required to be, an instance of a Django model. It may be None if the view is in the process of constructing a new instance.
The field on the current object instance that can be used to determine the name of a candidate template. If either template_name_field itself or the value of the template_name_field on the current object instance is None, the object will not be used for a candidate template name.
R possesses a simple generic function mechanism which can be used for an object?oriented style of programming. Method dispatch takes place based on the class of the first argument to the generic function.
Many R objects have a class attribute, a character vector giving the names of the classes from which the object inherits. (Functions oldClass and oldClass- get and set the attribute, which can also be done directly.)
If the object does not have a class attribute, it has an implicit class, notably , , or or the result of typeof(x) (which is similar to mode(x)), but for type and mode , where the following extra classes exist for the corresponding function calls: if, while, for
Note that for objects x of an implicit (or an S4) class, when a (S3) generic function foo(x) is called, method dispatch may use more classes than are returned by class(x), e.g., for a numeric matrix, the foo.numeric() method may apply. The exact full character vector of the classes which UseMethod() uses, is available as .class2(x) since R version 4.0.0. (This also applies to S4 objects when S3 dispatch is considered, see below.)
NULL objects (of implicit class ) cannot have attributes (hence no class attribute) and attempting to assign a class is an error.
When a generic function fun is applied to an object with class attribute c(, ), the system searches for a function called fun.first and, if it finds it, applies it to the object. If no such function is found, a function called fun.second is tried. If no class name produces a suitable function, the function fun.default is used (if it exists). If there is no class attribute, the implicit class is tried, then the default method.
The function class prints the vector of names of classes an object inherits from. Correspondingly, class- sets the classes an object inherits from. Assigning NULL removes the class attribute.
unclass returns (a copy of) its argument with its class attribute removed. (It is not allowed for objects which cannot be copied, namely environments and external pointers.)
isa tests whether x is an object of class(es) as given in what by using is if x is an S4 object, and otherwise giving TRUE iff all elements of class(x) are contained in what.
An additional mechanism of formal classes, nicknamed , is available in package methods which is attached by default. For objects which have a formal class, its name is returned by class as a character vector of length one and method dispatch can happen on several arguments, instead of only the first. However, S3 method selection attempts to treat objects from an S4 class as if they had the appropriate S3 class attribute, as does inherits. Therefore, S3 methods can be defined for S4 classes. See the ../../methods/help/Introduction.html and ../../base/help/Methods_for_S3.html help pages for basic information on S4 methods and for the relation between these and S3 methods.
The replacement version of the function sets the class to the value provided. For classes that have a formal definition, directly replacing the class this way is strongly deprecated. The expression as(object, value) is the way to coerce an object to a particular class.
Functions oldClass and oldClass- behave in the same way as functions of those names in S-PLUS 5/6, but in R UseMethod dispatches on the class as returned by class (with some interpolated classes: see the link) rather than oldClass. However, group generics dispatch on the oldClass for efficiency, and internal generics only dispatch on objects for which is.object is true.
Is the Gerund in the following sentences/questions used as a subject, object or as a complement?
We offer object fun
object fun, object, fun,