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Empty set literal?
...>> print(s)
set()
this is basically a more condensed way of doing {_ for _ in ()}, but, don't do this.
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Why is Python running my module when I import it, and how do I stop it?
...is:
# stuff to run always here such as class/def
def main():
pass
if __name__ == "__main__":
# stuff only to run when not called via 'import' here
main()
See What is if __name__ == "__main__" for?
It does require source control over the module being imported, however.
Happy coding.
...
micro:bit 实验01 - 手机连上 micro:bit，点亮第一行字 · App Inventor 2 中文网
... 负责扫描、连接、断开
参考文档
Microbit_Led
负责往 LED 点阵写文字/图案
com.bbc.microbit.profile-20200518.aix
导入方式：设计视图左侧组件面板拉到底 → Extension → Import extension → 选 .aix 文件。
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Python multiprocessing PicklingError: Can't pickle
...as mp
class Foo():
@staticmethod
def work(self):
pass
if __name__ == '__main__':
pool = mp.Pool()
foo = Foo()
pool.apply_async(foo.work)
pool.close()
pool.join()
yields an error almost identical to the one you posted:
Exception in thread Thread-2:
Tracebac...
What is the iPad user agent?
...
Mozilla/5.0(iPad; U; CPU iPhone OS 3_2 like Mac OS X; en-us) AppleWebKit/531.21.10 (KHTML, like Gecko) Version/4.0.4 Mobile/7B314 Safari/531.21.10
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Regex lookahead, lookbehind and atomic groups
...pression.info for more details.
Positive lookahead:
Syntax:
(?=REGEX_1)REGEX_2
Match only if REGEX_1 matches; after matching REGEX_1, the match is discarded and searching for REGEX_2 starts at the same position.
example:
(?=[a-z0-9]{4}$)[a-z]{1,2}[0-9]{2,3}
REGEX_1 is [a-z0-9]{4}$ which...
Run function from the command line
...() somewhere below the function and it will execute when you do python your_file.py
For a neater solution you can use this:
if __name__ == '__main__':
hello()
That way the function will only be executed if you run the file, not when you import the file.
...
String concatenation vs. string substitution in Python
...e interpolation/templating.
>>> import timeit
>>> def so_q_sub(n):
... return "%s%s/%d" % (DOMAIN, QUESTIONS, n)
...
>>> so_q_sub(1000)
'http://stackoverflow.com/questions/1000'
>>> def so_q_cat(n):
... return DOMAIN + QUESTIONS + '/' + str(n)
...
>>> ...
Can I serve multiple clients using just Flask app.run() as standalone?
...onal keyword arguments (**options) that it forwards to werkzeug.serving.run_simple - two of those arguments are threaded (a boolean) and processes (which you can set to a number greater than one to have werkzeug spawn more than one process to handle requests).
threaded defaults to True as of Flask ...
Asynchronous method call in Python?
...an use pools of processes and then get results asynchronously with:
apply_async(func[, args[, kwds[, callback]]])
E.g.:
from multiprocessing import Pool
def f(x):
return x*x
if __name__ == '__main__':
pool = Pool(processes=1) # Start a worker processes.
result = pool....