• Comparing equivalent Python statements

  While teaching one of my Python classes yesterday I noticed a conditional expression which can be written in several ways. All of these are equivalent in their behavior: if os.path.isdir(path) is False: pass if os.path.isdir(path) is not True: pass if os.path.isdir(path) == False: pass if os.path.isdir(path) != True: pass if not os.path.isdir(path): pass My preferred style of writing is the last one (not os.path.isdir()) because it looks the most pythonic of all. However the 5 expressions are slightly different behind the scenes so they must also have different speed of execution (click operator for link to documentation): is - identity operator, e.g. both arguments are the same object as determined by the id() function. In CPython that means both arguments point to the same address in memory is not - yields the inverse truth value of is, e.g. both arguments are not the same object (address) in memory == - equality operator, e.g. both arguments have the same value != - non-equality operator, e.g. both arguments have different values not - boolean operator In my initial tweet I mentioned that I think is False should be the fastest. Kiwi TCMS team member Zahari countered with not to be the fastest but didn't provide any reasoning! My initial reasoning was as follows: is is essentially comparing addresses in memory so it should be as fast as it gets == and != should be roughly the same but they do need to "read" values from memory which would take additional time before[…]

  6.12.2019 | 2:19 קרא עוד...

• Definition of the day: Error Guessing

    Hey everyone, Here is the definition of the day: Error Guessing A test technique in which tests are derived on the basis of the tester's knowledge of past failures, or general knowledge of failure modes. Examples When you find multiple bugs during a testing phase, once all the bugs have been fixed then you ... [Read more...] The post Definition of the day: Error Guessing appeared first on The Life Of One Man.

  6.12.2019 | 4:07 קרא עוד...

• Meme of the day: Project managers expecting their feature but then…

  The post Meme of the day: Project managers expecting their feature but then… appeared first on The Life Of One Man.

  6.12.2019 | 4:01 קרא עוד...

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