what is a keyword argument value's namespace in python?

This is why the name bar is not resolved in your second example:

class Foo:
   bar = 0
def __init__(self):
   self.a = bar # name "bar"
isn 't accessible here, but code is valid syntax

Foo() # NameError: name 'bar'
is not defined

You should now understand why the final example does work:

class Foo:
   bar = 0
def __init__(self, a = bar):
   self.a = a
Foo()

And, considering points 1-3 above, you should also be able to correctly predict what happens here:

class Foo:
   def __init__(self, a = bar):
   self.a = a
bar = 0
Foo()

Suggestion : 2

In this tutorial, you will learn about namespace, mapping from names to objects, and scope of a variable. ,In Python, you can imagine a namespace as a mapping of every name you have defined to corresponding objects.,This is the reason that built-in functions like id(), print() etc. are always available to us from any part of the program. Each module creates its own global namespace.,Here, the variable a is in the global namespace. Variable b is in the local namespace of outer_function() and c is in the nested local namespace of inner_function().

For example, when we do the assignment a = 2, 2 is an object stored in memory and a is the name we associate it with. We can get the address (in RAM) of some object through the built-in function id(). Let's look at how to use it.

# Note: You may get different values
for the id

a = 2
print('id(2) =', id(2))

print('id(a) =', id(a))

Output

id(2) = 9302208
id(a) = 9302208

Here, both refer to the same object 2, so they have the same id(). Let's make things a little more interesting.

# Note: You may get different values
for the id

a = 2
print('id(a) =', id(a))

a = a + 1
print('id(a) =', id(a))

print('id(3) =', id(3))

b = 2
print('id(b) =', id(b))
print('id(2) =', id(2))

All these are valid and a will refer to three different types of objects in different instances. Functions are objects too, so a name can refer to them as well.

def printHello():
   print("Hello")

a = printHello

a()

Example of Scope and Namespace in Python

def outer_function():
   b = 20
def inner_func():
   c = 30

a = 10

Suggestion : 3

Last Updated : 09 Feb, 2021,GATE CS 2021 Syllabus

Output:

Suggestion : 4

The name (left side) of a default argument is a local variable name inside the function body.,The value (right side) of a default argument is evaluated in the scope where the function is defined, at the time of function definition.,Now this successfully assigns value held by anycodings_python a class variable foo to an object a inside anycodings_python the initializer. Why do these things happen anycodings_python and how are the default argument values anycodings_python treated?,There's more information about the weird anycodings_python class scope over in UnboundLocalError: anycodings_python local variable referenced before anycodings_python assignment why LEGB Rule not applied in anycodings_python this case.

I know python treats this namespace in a anycodings_python different way ever since I found out about

def foo(l = []):
   l.append(1)
print(l)

foo()
foo()
foo([])
foo()

which prints the following.

[1]
[1, 1]
[1]
[1, 1, 1]

So I was sceptical about their use as an anycodings_python object initializers. Then recently I anycodings_python encountered another similarly strange anycodings_python behaviour, demonstrated below.

class Foo:
   bar = 0
def __init__(self):
   self.a = bar
Foo()

This is why the name bar is not resolved anycodings_python in your second example:

class Foo:
   bar = 0
def __init__(self):
   self.a = bar # name "bar"
isn 't accessible here, but code is valid syntax

Foo() # NameError: name 'bar'
is not defined

You should now understand why the final anycodings_python example does work:

class Foo:
   bar = 0
def __init__(self, a = bar):
   self.a = a
Foo()

And, considering points 1-3 above, you anycodings_python should also be able to correctly predict anycodings_python what happens here:

class Foo:
   def __init__(self, a = bar):
   self.a = a
bar = 0
Foo()

Suggestion : 5

The namespace helps the Python interpreter to understand what exact method or variable is trying to point out in the code. So its name gives more information - Name (which means name, a unique identifier) + Space (related to scope).,The Python interpreter creates a global namespace for any module that our Python loads with the import statement. To get more information, visit our Python Module.,As these namespace various have lifetimes, Python interpreter creates namespaces as necessary and deletes them when they are no longer needed.,The global namespace consists of any names in Python at any level of the main program. It is created when the main body executes and remains in existence until the interpreter terminates.

['ArithmeticError', 'AssertionError', 'AttributeError', 'BaseException', 'BlockingIOError', 'BrokenPipeError', 'BufferError', 'BytesWarning', 'ChildProcessError', 'ConnectionAbortedError', 'ConnectionError', 'ConnectionRefusedError', 'ConnectionResetError', 'DeprecationWarning', 'EOFError', 'Ellipsis', 'EnvironmentError', 'Exception', 'False', 'FileExistsError', 'FileNotFoundError', 'FloatingPointError', 'FutureWarning', 'GeneratorExit', 'IOError', 'ImportError', 'ImportWarning', 'IndentationError', 'IndexError', 'InterruptedError', 'IsADirectoryError', 'KeyError', 'KeyboardInterrupt', 'LookupError', 'MemoryError', 'ModuleNotFoundError', 'NameError', 'None', 'NotADirectoryError', 'NotImplemented', 'NotImplementedError', 'OSError', 'OverflowError', 'PendingDeprecationWarning', 'PermissionError', 'ProcessLookupError', 'RecursionError', 'ReferenceError', 'ResourceWarning', 'RuntimeError', 'RuntimeWarning', 'StopAsyncIteration', 'StopIteration', 'SyntaxError', 'SyntaxWarning', 'SystemError', 'SystemExit', 'TabError',
   'TimeoutError', 'True', 'TypeError', 'UnboundLocalError', 'UnicodeDecodeError', 'UnicodeEncodeError', 'UnicodeError', 'UnicodeTranslateError', 'UnicodeWarning', 'UserWarning', 'ValueError', 'Warning', 'WindowsError', 'ZeroDivisionError', '__build_class__', '__debug__', '__doc__', '__import__', '__loader__', '__name__', '__package__', '__spec__', 'abs', 'all', 'any', 'ascii', 'bin', 'bool', 'breakpoint', 'bytearray', 'bytes', 'callable',
   'chr', 'classmethod', 'compile', 'complex', 'copyright', 'credits', 'delattr', 'dict', 'dir', 'divmod', 'enumerate', 'eval', 'exec', 'exit', 'filter', 'float', 'format', 'frozenset', 'getattr', 'globals', 'hasattr', 'hash', 'help', 'hex', 'id', 'input', 'int', 'isinstance', 'issubclass', 'iter', 'len', 'license', 'list', 'locals', 'map', 'max', 'memoryview', 'min', 'next', 'object', 'oct', 'open', 'ord', 'pow', 'print', 'property', 'quit', 'range', 'repr', 'reversed', 'round', 'set', 'setattr', 'slice', 'sorted', 'staticmethod', 'str', 'sum', 'super', 'tuple', 'type', 'vars', 'zip'
]

Inside scope_func
Inside inner
function, value of
   var: 20
Traceback(most recent call last):
   File "d:/Python Project/listproblems.py", line 343, in
scope_func()
File "d:/Python Project/listproblems.py", line 342, in scope_func
print("Try printing var from outer function: ",
   var)
NameError: name 'var'
is not defined

40
20

['A', 'B', 'C', 'D', 'E']

Suggestion : 6

keyword argument: an argument preceded by an identifier (e.g. name=) in a function call or passed as a value in a dictionary preceded by **. For example, 3 and 5 are both keyword arguments in the following calls to complex():,keyword argument: an argument preceded by an identifier (e.g. name=) in a function call or passed as a value in a dictionary preceded by **. For example, 3 and 5 are both keyword arguments in the following calls to complex(): complex(real=3, imag=5) complex(**{'real': 3, 'imag': 5}) ,A named entity in a function (or method) definition that specifies an argument (or in some cases, arguments) that the function can accept. There are five kinds of parameter:,positional-or-keyword: specifies an argument that can be passed either positionally or as a keyword argument. This is the default kind of parameter, for example foo and bar in the following:

complex(real = 3, imag = 5)
complex( ** {
   'real': 3,
   'imag': 5
})

complex(3, 5)
complex( * (3, 5))

def f(arg):
   ...
   f = staticmethod(f)

@staticmethod
def f(arg):
   ...

def sum_two_numbers(a: int, b: int) - > int:
   return a + b

>>>
import __future__
   >>>
   __future__.division
_Feature((2, 2, 0, 'alpha', 2), (3, 0, 0, 'alpha', 0), 8192)

>>> sum(i * i
   for i in range(10)) # sum of squares 0, 1, 4, ...81
285