isinstance

How to find/detect if a build-in function is used in Python AST?

由 只谈情不闲聊 提交于 2019-12-08 11:28:12
问题 The goal is to detect if a builtin function such as eval() is used in some code. def foo(a): eval('a = 2') I have tried the following approach: ex_ast = ast.parse(inspect.getsource(foo)) for node in ast.walk(ex_ast): if isinstance(node, ast.FunctionDef): print(node.name) The function name foo is printed as the output. I know that Builtin functions don't have constructors. They are in the type Module. So 1 approach would be using types.FunctionType in an isinstance call. But since I'm using

Making 'isinstance' work with decorators

由 只谈情不闲聊 提交于 2019-12-08 02:53:36
问题 How does the Python isinstance function work internally? Is there anything I can do to alter its results, like define a special function inside a class or something? Here's my use case: class Decorator: def __init__(self, decorated): self._decorated = decorated def __call__(self): return self._decorated() @Decorator class Foo: pass f = Foo() # How can I make this be true? isinstance(f, Foo) Decorator acts almost like a mixin, except a mixing wouldn't be appropriate here. Is there any way I

How to check a specific type of tuple or list?

由 删除回忆录丶 提交于 2019-12-07 22:08:59
问题 Suppose, var = ('x', 3) How to check if a variable is a tuple with only two elements, first being a type str and the other a type int in python? Can we do this using only one check? I want to avoid this - if isinstance(var, tuple): if isinstance (var[0], str) and (var[1], int): return True return False 回答1: Here's a simple one-liner: isinstance(v, tuple) and list(map(type, v)) == [str, int] Try it out: >>> def check(v): return isinstance(v, tuple) and list(map(type, v)) == [str, int] ... >>>

How to check a specific type of tuple or list?

由 走远了吗. 提交于 2019-12-06 09:42:00
Suppose, var = ('x', 3) How to check if a variable is a tuple with only two elements, first being a type str and the other a type int in python? Can we do this using only one check? I want to avoid this - if isinstance(var, tuple): if isinstance (var[0], str) and (var[1], int): return True return False Here's a simple one-liner: isinstance(v, tuple) and list(map(type, v)) == [str, int] Try it out: >>> def check(v): return isinstance(v, tuple) and list(map(type, v)) == [str, int] ... >>> check(0) False >>> check(('x', 3, 4)) False >>> check((3, 4)) False >>> check(['x', 3]) False >>> check(('x'

PHP check for instance of DateTime?

由 扶醉桌前 提交于 2019-12-05 08:21:12
问题 Is this the only way to check if an object is an instance of a class, in my case of the DateTime class? $cls = ReflectionClass("DateTime"); if (! $cls->isInstance( (object) $var ) ) { // is not an instance } It seems a bit heavy to me. 回答1: You could try instanceof­Docs... if ($var instanceof DateTime) { // true } See also is_a­Docs: if (is_a($var, 'DateTime')) { // true } 回答2: if ($var instanceof DateTime) 回答3: You can use get_class function like this: <?php $a = new DateTime(); if (get

“Protocols cannot be used with isinstance()” - why not?

由 ﹥＞﹥吖頭↗ 提交于 2019-12-04 17:53:30
问题 The new typing module contains several objects with names like "SupportsInt" (-Float, -Bytes, etc.). The name, and the descriptions on the documentation page for the module, might be read to suggest that you can test whether an object is of a type that "supports __int__() ". But if you try to use isinstance() , it gives a response that makes it clear that that isn't something you are meant to do: >>> isinstance(5, typing.SupportsInt) (Traceback omitted) TypeError: Protocols cannot be used

“Protocols cannot be used with isinstance()” - why not?

由 半腔热情 提交于 2019-12-03 11:52:22
The new typing module contains several objects with names like "SupportsInt" (-Float, -Bytes, etc.). The name, and the descriptions on the documentation page for the module , might be read to suggest that you can test whether an object is of a type that "supports __int__() ". But if you try to use isinstance() , it gives a response that makes it clear that that isn't something you are meant to do: >>> isinstance(5, typing.SupportsInt) (Traceback omitted) TypeError: Protocols cannot be used with isinstance(). On the other hand, you can use issubclass() : >>> issubclass((5).__class__, typing

Python check if isinstance any type in list?

由 爷，独闯天下 提交于 2019-12-03 10:27:08
问题 How do I pythonicly do: var = 7.0 var_is_good = isinstance(var, classinfo1) or isinstance(var, classinfo2) or isinstance(var, classinfo3) or ... or isinstance(var, classinfoN) It seems silly I can't just pass in a list of classinfo's: var_is_good = isinstanceofany( var, [classinfo1, classinfo2, ... , classinfoN] ) So what is the isinstanceofany function? 回答1: isinstance() takes a tuple of classes for the second argument. It'll return true if the first argument is an instance of any of the

Python check if isinstance any type in list?

由 拜拜、爱过 提交于 2019-12-03 04:10:00
How do I pythonicly do: var = 7.0 var_is_good = isinstance(var, classinfo1) or isinstance(var, classinfo2) or isinstance(var, classinfo3) or ... or isinstance(var, classinfoN) It seems silly I can't just pass in a list of classinfo's: var_is_good = isinstanceofany( var, [classinfo1, classinfo2, ... , classinfoN] ) So what is the isinstanceofany function? isinstance() takes a tuple of classes for the second argument. It'll return true if the first argument is an instance of any of the types in that sequence: isinstance(var, (classinfo1, classinfo2, classinfo3)) In other words, isinstance()

Checking if an annotation is of a specific type

由 怎甘沉沦 提交于 2019-12-02 19:16:26
I am using reflection to see if an annotation that is attached to a property of a class, is of a specific type. Current I am doing: if("javax.validation.Valid".equals(annotation.annotationType().getName())) { ... } Which strikes me as a little kludgey because it relies on a string that is a fully-qualified class-name. If the namespace changes in the future, this could cause subtle errors. I would like to do: if(Class.forName(annotation.annotationType().getName()).isInstance( new javax.validation.Valid() )) { ... } But javax.validation.Valid is an abstract class and cannot be instantiated. Is
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