python - What is the purpose of the return statement? How is it ...
In python, we start defining a function with def, and generally - but not necessarily - end the function with return. Suppose we want a function that adds 2 to the input value x . In mathematics, we might write something like f(x) = x + 2 , describing that relationship: the value of the function, evaluated at x , is equal to x + 2 .
python - what is the need to use return 1 or -1 in the end of a ...
2020年7月28日 · In your code for instance: you return 1 if the if condition checks out, and return -1 if the condition is not satisfied. The caller of the function add_user() might want to perform an operation based on if the user was added or not, so returning 1 or -1 is a way the programmer can handle the next logic.
python - It is more efficient to use if-return-return or if-else-return ...
2012年2月8日 · Besides the single-exit-point rule being old-fashioned and overly "engineeringy", Python specifically promotes a "flat is better than nested" view, and putting return wherever it happens to be clear is the idiomatic way to do it in Python.
python - Using "and" in return - Stack Overflow
return username and USER_RE.match(username) is the same as: if username: return USER_RE.match(username) else: return username Strings like username are truish if they are not empty. The regex match function returns a truish match object if the pattern matches, and returns None, a falsish value, if it doesn't match.
Python lists append return value - Stack Overflow
2009年12月17日 · Please do not transliterate code from other languages into Python. Please try to think about how Python actually works; please think about how the algorithm actually works. Then -- after understanding -- write the Python. Simply replace C-language tokens with Python tokens will rarely give you working Python. –
How can I return two values from a function in Python?
def select_choice(): ... return i, card # or [i, card] my_i, my_card = select_choice() On line return i, card i, card means creating a tuple. You can also use parenthesis like return (i, card), but tuples are created by comma, so parens are not mandatory. But you can use parens to make your code more readable or to split the tuple over multiple ...
python - What does return -1 here mean? - Stack Overflow
2021年2月23日 · Maybe the writer was thinking of unsigned integers, which don't exist in Python (at least not as a native type). There are a bunch of other oddities that make me think it was written by someone more familiar with say, C, than Python (namely, passing in the length of an array, looping over numbers with while instead of for ... range , referring ...
How to return value from async method in python?
2017年3月16日 · On second thought: what you probably want to do is loop.create_task(conn.close()) and still use return values. This will schedule the closing of the connection without waiting for it in your function.
Manually raising (throwing) an exception in Python
2022年6月13日 · def crash(): return 0/0 It does not allow you to throw a specific message to your user but will crash the python interpriter. For the more advanced python users who have used python may think that the expression will be evaluated at compile time (python is compiled) but the python compiler wont evaluate the expression at run time.
How to return a value from __init__ in Python? - Stack Overflow
2010年3月22日 · Python does not allow to return anything from __init__, but you may write a factory function, or a class method, or a Parser class, depending on the code structure and complexity of parsing, which will parse your data into data objects. Global variable is not a good solution, as it may be changed somewhere else, breaking the parsing logic.