What does the term pass mean in python? [duplicate] - python

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How to use "pass" statement?
(18 answers)
Closed 6 years ago.
What does pass mean in python? I have seen it used and I do not see why you need to use it or what it does? I guess I could say it passes over whatever function it is in, but why include it?

Quoth the doc:
The pass statement does nothing. It can be used when a statement is required syntactically but the program requires no action.
References:
https://docs.python.org/2/reference/simple_stmts.html#the-pass-statement
https://docs.python.org/2/tutorial/controlflow.html#pass-statements

"It is used when a statement is required syntactically but you do not want any command or code to execute.
The pass statement is a null operation; nothing happens when it executes. The pass is also useful in places where your code will eventually go, but has not been written yet (e.g., in stubs for example):"
https://www.tutorialspoint.com/python/python_pass_statement.htm

Related

Obtaining closures at runtime [duplicate]

This question already has answers here:
Given a function with closure, can I refer back to it's closure scope?
(1 answer)
What exactly is contained within a obj.__closure__?
(4 answers)
Closed 2 years ago.
I would like to know if there is any method to check whether two functions have the same arguments at runtime in python 3.
Basically, I have this function (func) that takes another function and an argument. I want to check the values assigned to args in the lambda function
func(another_func, args):
return lambda(x : another_func(x, args))
It is not feasible to run the code before and check the results because I am implementing a lazy framework. My main goal is to be able to understand what are the arguments of the function because there is one variable argument that I do not care but there is one static that is created before running the function.
##EDIT
I actually solved this problem using the inspect module (getclosure) for those who are interested!
I actually solved this problem using the inspect module (getclosure) for those who are interested!
Extension (Martijn Pieters):
I think you are referring to getclosurevars(). You can also just access function.closure, and access the value of each cell via its cell_contents attribute.

Is it possible to declare a function called 'except' in Python? [duplicate]

This question already has answers here:
Is it possible to escape a reserved word in Python?
(5 answers)
Closed 2 years ago.
Currently I am trying to implement an API in Python that originally was written in another programming language. This API has a function called except. I am trying to implement this function in Python but obviously this resulted in an error as except is already part of the Python language. It's probably bad practice, but does someone know if it's even possible to declare a function called except?
def except():
print('hi')
>>>
def except():
^
SyntaxError: invalid syntax
It's not possible; except is a Python keyword and cannot be used as a user-defined name in any way. You can find the complete list of keywords through the keyword module.
No it is a reserved keywords. They can't be used to declare a variable or a function.
You can't declare a method named "except" cause "except" is a reserved keyword in python but you can use "Except"

how to use print both as a function and a variable in one program [duplicate]

This question already has answers here:
Why does code like `str = str(...)` cause a TypeError, but only the second time?
(20 answers)
Closed 6 years ago.
I have used print to store value like:
print=3
After then I am not able to use it to print any message:
print('a message')
Its giving error:
'int object is not callable'
Is there any way to use print both as a variable and a functions? If not then Why not python just makes built-in function names as keyword to remove this conflict?
Functions and data share the same namespace in Python -- as they do in many other languages (the entire family of LISP-1s comes to mind first, including Scheme and Clojure; also Ruby, Groovy, and I'm sure many more).
Thus no, you cannot do this. Widely available checkers (pylint, pychecker, etc) will catch and report on attempts to shadow builtins (such as print) with data.

Proper Python Syntax and Semantics: if, else, pass [duplicate]

This question already has answers here:
Using pass on a non necessary else statement
(5 answers)
Closed 8 years ago.
Is there a preferred/proper style?
This:
def fx(Boolean):
if Boolean:
# Do stuff.
else:
pass
Or this:
def fx(Boolean):
if Boolean:
# Do stuff.
Is it preferred/proper to include else: pass if you don't want anything to happen?
I've read PEP 8 - Style Guide for Python Code and did not find anything concerning my question.
You should never include else: pass. It's superfluous. Just omit the else; it's intentionally an optional keyword.
If you don't need the else if there is no reason to add it. It will just confuse other people reading your code in the future (ie yourself a few months later).

Why does Python require the "self" parameter? [duplicate]

This question already has answers here:
Closed 12 years ago.
Possible Duplicates:
python ‘self’ explained
Why do you need explicitly have the “self” argument into a Python method?
Why does Python require the "self" parameter for methods?
For example def method_abc(self, arg1)
And is there ever a date that the need for it will be removed?
Python gives you the option of naming it something other than self, even though the standard is to name it self. Just as it gives you the option of using tabs for indents, even though the standard is to use spaces.
In other words, it's not just "assumed" because...
To give you naming flexibility
To make it clearer that something will be passed self (or not).

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