dir():
print(dir())
"""output
['__annotations__', '__builtins__', '__doc__',
'__file__', '__loader__', '__name__',
'__package__', '__spec__'] """
Python provides in built function dir()
which displays all the members of currently running the program or module.
Syntax:
dir()
dir(specified module name)
Example
2: to get the modules information
#f:/Programs/Modules/tes2.py
import cali
print(dir())
print(dir(cali))
"""output
['__annotations__', '__builtins__',
'__doc__', '__file__', '__loader__', '__name__', '__package__', '__spec__',
'cali'] ['__builtins__', '__cached__', '__doc__', '__file__', '__loader__',
'__name__', '__package__', '__spec__', 'add', 'div', 'mul', 'sub']
>>>
Note: For every module/program Python interpreter adds some
special members (ex: variables/functions/classes) automatically for internal
use.
Based on our requirement we can access
these member/properties in our program.
"""
__name__ (double underscore before and after)
Example
code:
print(__name__)
Output:
__main__
Example
2:
#f:/Programs/Modules/tes2.py
def display():
if __name__=='__main__':
print("The code executed as a program")
else:
print("This prog executed as a module from some other
program")
output:
The code executed as a program
Here name contains main variable
Example
3:
#F:/Programs/Modules/test2.py
def display():
if __name__=='__main__':
print("The code executed as a program")
else:
print("This prog executed as a module from some other
program")
#Testing
_name_
#F:/Programs/Modules/disp.py
import test2
test2.display()
"""
Note: __name__ contains test2
output
This prog executed as a module from some
other program
"""
In c, c++, java main is the starting
point of execution. For example when you
are working any project, it may have multiple modules, in those modules but
there will be one module you will execute first.
For example this test2.py is the first
module, first module name always is __main__(double underscore before main and
after main)
For every python program, some
members added internally, here __name__ is added internally. This variable __name__ stores
information regarding whether the program is executed as an individual program
or as a module.
·
If the program
executed as an individual program then the value this variable __name__ is
__main__.
·
If the program
executed as module from some other program then the value of this variable
__name__ is name of the module (i.e __name__=test2) where it is defined.
Note: So by using this __name__ variable we can identify whether the program
executed directly or as a module
Related video: https://www.youtube.com/watch?v=DZpN8_7i9l8&feature=youtu.be
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