Use isinstance to check if o is an instance of str or any subclass of str: if isinstance(o, str): To check if the type of o is exactly str, excluding subclasses of str: if type(o) is str: Another alternative to the above: if issubclass(type(o), str): See Built-in Functions in the Python Library Reference for relevant … Read more
What? Floats are immutable? But can’t I do x = 5.0 x += 7.0 print x # 12.0 Doesn’t that “mut” x? Well you agree strings are immutable right? But you can do the same thing. s=”foo” s += ‘bar’ print s # foobar The value of the variable changes, but it changes by changing … Read more
From New-style and classic classes: Up to Python 2.1, old-style classes were the only flavour available to the user. The concept of (old-style) class is unrelated to the concept of type: if x is an instance of an old-style class, then x.__class__ designates the class of x, but type(x) is always <type ‘instance’>. This reflects … Read more
From the python 2 manual: CPython implementation detail: Objects of different types except numbers are ordered by their type names; objects of the same types that don’t support proper comparison are ordered by their address. When you order two strings or two numeric types the ordering is done in the expected way (lexicographic ordering for … Read more
You have four main options for converting types in pandas: to_numeric() – provides functionality to safely convert non-numeric types (e.g. strings) to a suitable numeric type. (See also to_datetime() and to_timedelta().) astype() – convert (almost) any type to (almost) any other type (even if it’s not necessarily sensible to do so). Also allows you to … Read more
POD stands for Plain Old Data – that is, a class (whether defined with the keyword struct or the keyword class) without constructors, destructors and virtual members functions. Wikipedia’s article on POD goes into a bit more detail and defines it as: A Plain Old Data Structure in C++ is an aggregate class that contains … Read more
Use the type() builtin function: >>> i = 123 >>> type(i) <type ‘int’> >>> type(i) is int True >>> i = 123.456 >>> type(i) <type ‘float’> >>> type(i) is float True To check if a variable is of a given type, use isinstance: >>> i = 123 >>> isinstance(i, int) True >>> isinstance(i, (float, str, … Read more
There are two built-in functions that help you identify the type of an object. You can use type() if you need the exact type of an object, and isinstance() to check an object’s type against something. Usually, you want to use isinstance() most of the times since it is very robust and also supports type … Read more
Since the pointer returned by malloc() is sufficiently well aligned to be used as a pointer to any type, you could (but probably shouldn’t) use: assert(sizeof(float) <= 10); void *data = malloc(10); char *str = data; strcpy(str, “123.4”); float *vp = data; *vp = strtof(str, NULL); …use *vp… free(data); And now you can use *vp … Read more
Variables of type int, bool, double, char, etc. are NOT objects. These types are called primitive types, so no constructor/destructor outside of memory allocation/deallocation. Look them up for more details.