Python Download Type File
Daniel Mcmillen
Python is a dynamically-typed language. So, if we want to know the type of the arguments, we can use the type() function. If you want to make sure that your function works only on the specific types of objects, use isinstance() function.
Some operations are supported by several object types; in particular,practically all objects can be compared for equality, tested for truthvalue, and converted to a string (with the repr() function or theslightly different str() function). The latter function is implicitlyused when an object is written by the print() function.
Instances of a class cannot be ordered with respect to other instances of thesame class, or other types of object, unless the class defines enough of themethods __lt__(), __le__(), __gt__(), and__ge__() (in general, __lt__() and__eq__() are sufficient, if you want the conventional meanings of thecomparison operators).
Return an iterator object. The object is required to support theiterator protocol described below. If a container supports different typesof iteration, additional methods can be provided to specifically requestiterators for those iteration types. (An example of an object supportingmultiple forms of iteration would be a tree structure which supports bothbreadth-first and depth-first traversal.) This method corresponds to thetp_iter slot of the type structure for Pythonobjects in the Python/C API.
Return the iterator object itself. This is required to allow bothcontainers and iterators to be used with the for andin statements. This method corresponds to thetp_iter slot of the type structure for Pythonobjects in the Python/C API.
Return the next item from the iterator. If there are no furtheritems, raise the StopIteration exception. This method corresponds tothe tp_iternext slot of the type structure forPython objects in the Python/C API.
Python defines several iterator objects to support iteration over general andspecific sequence types, dictionaries, and other more specialized forms. Thespecific types are not important beyond their implementation of the iteratorprotocol.
This table lists the sequence operations sorted in ascending priority. In thetable, s and t are sequences of the same type, n, i, j and k areintegers and x is an arbitrary object that meets any type and valuerestrictions imposed by s.
Sequences of the same type also support comparisons. In particular, tuplesand lists are compared lexicographically by comparing corresponding elements.This means that to compare equal, every element must compare equal and thetwo sequences must be of the same type and have the same length. (For fulldetails see Comparisons in the language reference.)
Values of n less than 0 are treated as 0 (which yields an emptysequence of the same type as s). Note that items in the sequence sare not copied; they are referenced multiple times. This often hauntsnew Python programmers; consider:
In the table s is an instance of a mutable sequence type, t is anyiterable object and x is an arbitrary object that meets any typeand value restrictions imposed by s (for example, bytearray onlyaccepts integers that meet the value restriction 0
The advantage of the range type over a regular list ortuple is that a range object will always take the same(small) amount of memory, no matter the size of the range it represents (as itonly stores the start, stop and step values, calculating individualitems and subranges as needed).
Strings also support two styles of string formatting, one providing a largedegree of flexibility and customization (see str.format(),Format String Syntax and Custom String Formatting) and the other based on Cprintf style formatting that handles a narrower range of types and isslightly harder to use correctly, but is often faster for the cases it canhandle (printf-style String Formatting).
When formatting a number (int, float, complex,decimal.Decimal and subclasses) with the n type(ex: ':n'.format(1234)), the function temporarily sets theLC_CTYPE locale to the LC_NUMERIC locale to decodedecimal_point and thousands_sep fields of localeconv() ifthey are non-ASCII or longer than 1 byte, and the LC_NUMERIC locale isdifferent than the LC_CTYPE locale. This temporary change affectsother threads.
When the right argument is a dictionary (or other mapping type), then theformats in the string must include a parenthesised mapping key into thatdictionary inserted immediately after the '%' character. The mapping keyselects the value to be formatted from the mapping. For example:
Since 2 hexadecimal digits correspond precisely to a single byte, hexadecimalnumbers are a commonly used format for describing binary data. Accordingly,the bytes type has an additional class method to read data in that format:
Since 2 hexadecimal digits correspond precisely to a single byte, hexadecimalnumbers are a commonly used format for describing binary data. Accordingly,the bytearray type has an additional class method to read data in that format:
Split the binary sequence into subsequences of the same type, using sepas the delimiter string. If maxsplit is given, at most maxsplit splitsare done, the rightmost ones. If sep is not specified or None,any subsequence consisting solely of ASCII whitespace is a separator.Except for splitting from the right, rsplit() behaves likesplit() which is described in detail below.
Split the binary sequence into subsequences of the same type, using sepas the delimiter string. If maxsplit is given and non-negative, at mostmaxsplit splits are done (thus, the list will have at most maxsplit+1elements). If maxsplit is not specified or is -1, then there is nolimit on the number of splits (all possible splits are made).
When the right argument is a dictionary (or other mapping type), then theformats in the bytes object must include a parenthesised mapping key into thatdictionary inserted immediately after the '%' character. The mapping keyselects the value to be formatted from the mapping. For example:
A memoryview has the notion of an element, which is theatomic memory unit handled by the originating object. For many simpletypes such as bytes and bytearray, an element is a singlebyte, but other types such as array.array may have bigger elements.
If format is one of the native format specifiersfrom the struct module, indexing with an integer or a tuple ofintegers is also supported and returns a single element withthe correct type. One-dimensional memoryviews can be indexedwith an integer or a one-integer tuple. Multi-dimensional memoryviewscan be indexed with tuples of exactly ndim integers where ndim isthe number of dimensions. Zero-dimensional memoryviews can be indexedwith the empty tuple.
Exit the runtime context and return a Boolean flag indicating if any exceptionthat occurred should be suppressed. If an exception occurred while executing thebody of the with statement, the arguments contain the exception type,value and traceback information. Otherwise, all three arguments are None.
Python defines several context managers to support easy thread synchronisation,prompt closure of files or other objects, and simpler manipulation of the activedecimal arithmetic context. The specific types are not treated specially beyondtheir implementation of the context management protocol. See thecontextlib module for some examples.
Note that there is no specific slot for any of these methods in the typestructure for Python objects in the Python/C API. Extension types wanting todefine these methods must provide them as a normal Python accessible method.Compared to the overhead of setting up the runtime context, the overhead of asingle class dictionary lookup is negligible.
For a container class, theargument(s) supplied to a subscription of the class mayindicate the type(s) of the elements an object contains. For example,set[bytes] can be used in type annotations to signify a set inwhich all the elements are of type bytes.
For a class which defines __class_getitem__() but is not acontainer, the argument(s) supplied to a subscription of the class will oftenindicate the return type(s) of one or more methods defined on an object. Forexample, regular expressions can be used on both the str datatype and the bytes data type:
If x = re.search('foo', 'foo'), x will be are.Match object where the return values ofx.group(0) and x[0] will both be of type str. We canrepresent this kind of object in type annotations with the GenericAliasre.Match[str].
If y = re.search(b'bar', b'bar'), (note the b for bytes),y will also be an instance of re.Match, but the returnvalues of y.group(0) and y[0] will both be of typebytes. In type annotations, we would represent thisvariety of re.Match objects with re.Match[bytes].
Another example for mapping objects, using a dict, whichis a generic type expecting two type parameters representing the key typeand the value type. In this example, the function expects a dict withkeys of type str and values of type int:
The Python runtime does not enforce type annotations.This extends to generic types and their type parameters. When creatinga container object from a GenericAlias, the elements in the container are not checkedagainst their type. For example, the following code is discouraged, but willrun without errors:
Defines a union object which holds types X, Y, and so forth. X Ymeans either X or Y. It is equivalent to typing.Union[X, Y].For example, the following function expects an argument of typeint or float:
There are really two flavors of function objects: built-in functions anduser-defined functions. Both support the same operation (to call the function),but the implementation is different, hence the different object types.
This object is commonly used by slicing (see Slicings). It supports nospecial operations. There is exactly one ellipsis object, namedEllipsis (a built-in name). type(Ellipsis)() produces theEllipsis singleton.
I have avoided the method body because I am only interested in the type hinting part for survey_id? Looks like it means it could be either int or str. I thought if that was the intention then it should have been survey_id: Union(int,str). PyCharm is not objecting. Do you think I missed something in PEP 484? I do not think it was meant to be a tuple.
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