安裝中文字典英文字典辭典工具!
安裝中文字典英文字典辭典工具!
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- What is Pythons equivalent of (logical-and) in an if-statement?
There is no bitwise negation in Python (just the bitwise inverse operator ~ - but that is not equivalent to not) See also 6 6 Unary arithmetic and bitwise binary operations and 6 7 Binary arithmetic operations The logical operators (like in many other languages) have the advantage that these are short-circuited That means if the first operand already defines the result, then the second
- slice - How slicing in Python works - Stack Overflow
Python slicing is a computationally fast way to methodically access parts of your data In my opinion, to be even an intermediate Python programmer, it's one aspect of the language that it is necessary to be familiar with
- What does [:-1] mean do in python? - Stack Overflow
Working on a python assignment and was curious as to what [:-1] means in the context of the following code: instructions = f readline()[:-1] Have searched on here on S O and on Google but to no avail
- python - What is the purpose of the -m switch? - Stack Overflow
Python 2 4 adds the command line switch -m to allow modules to be located using the Python module namespace for execution as scripts The motivating examples were standard library modules such as pdb and profile, and the Python 2 4 implementation is fine for this limited purpose
- operators - Python != operation vs is not - Stack Overflow
In a comment on this question, I saw a statement that recommended using result is not None vs result != None What is the difference? And why might one be recommended over the other?
- python - What does the b character do in front of a string literal . . .
I don't think this applies to Python I did find this documentation on the Python site about using a u character in the same syntax to specify a string as Unicode Unfortunately, it doesn't mention the b character anywhere in that document Also, just out of curiosity, are there more symbols than the b and u that do other things?
- What is the python keyword with used for? - Stack Overflow
In python the with keyword is used when working with unmanaged resources (like file streams) It is similar to the using statement in VB NET and C# It allows you to ensure that a resource is "cleaned up" when the code that uses it finishes running, even if exceptions are thrown It provides 'syntactic sugar' for try finally blocks From Python
- python - Iterating over a dictionary using a for loop, getting keys . . .
In Python 3, the iteration has to be over an explicit copy of the keys (otherwise it throws a RuntimeError) because my_dict keys() returns a view of the dictionary keys, so any change to my_dict changes the view as well
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