What happens "behind the scenes" if I call `None == x` in Python? Question: I am learning and playing around with Python and I came up with the following test code (please be aware that I would not write productive code like that, but when learning new languages I like to play around with the …
Can a string and int comparison be ever True in python2.7 Question: I know python2.7 allows comparison between different types. So the equality comparison between str and int will result in False. Can the comparison ever be true depending on the values of a and b? a = input(‘we input some string value a’) if …
Is there an operation for not less than or not greater than in python? Question: Suppose I have this code: a = 0 if a == 0 or a > 0: print(a) That is: I want to do something when a is not negative. I know that I can write if a != 0: to …
Sympy – Comparing expressions Question: Is there a way to check if two expressions are mathematically equal? I expected tg(x)cos(x) == sin(x) to output True, but it outputs False. Is there a way to make such comparisons with sympy? Another example is (a+b)**2 == a**2 + 2*a*b + b**2 which surprisingly also outputs False. I …
Why does "not(True) in [False, True]" return False? Question: If I do this: >>> False in [False, True] True That returns True. Simply because False is in the list. But if I do: >>> not(True) in [False, True] False That returns False. Whereas not(True) is equal to False: >>> not(True) False Why? Asked By: Texom512 …
What is the pythonic way to test whether two objects are the same, not just equal Question: My solution has been to make the object’s address into a string, which should always be unique. Below is a case where it works both ways, comparing the objects and comparing the values of str(object_a) and str(object_b). >>> …
Python's in (__contains__) operator returns a bool whose value is neither True nor False Question: As expected, 1 is not contained by the empty tuple >>> 1 in () False but the False value returned is not equal to False >>> 1 in () == False False Looking at it another way, the in operator …
How to check if the string is empty? Question: Does Python have something like an empty string variable where you can do: if myString == string.empty: Regardless, what’s the most elegant way to check for empty string values? I find hard coding “” every time for checking an empty string not as good. Asked By: …
Why is 'True == not False' a SyntaxError? Question: Comparing boolean values with == works in Python. But when I apply the boolean not operator, the result is a syntax error: Python 2.7 (r27:82500, Sep 16 2010, 18:02:00) [GCC 4.5.1 20100907 (Red Hat 4.5.1-3)] on linux2 Type “help”, “copyright”, “credits” or “license” for more information. …
Why does the expression 0 < 0 == 0 return False in Python? Question: Looking into Queue.py in Python 2.6, I found this construct that I found a bit strange: def full(self): “””Return True if the queue is full, False otherwise (not reliable!).””” self.mutex.acquire() n = 0 < self.maxsize == self._qsize() self.mutex.release() return n If …
