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A non-blocking read on a subprocess.PIPE in Python
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A reliable way to read a stream without blocking regardless of operating system is to use Queue.get_nowait():
import sys
from subprocess import PIPE, Popen
from threading import Thread
try:
from queue import Queue, Empty
except ImportError:
from Queue import Queue, Empty # python 2.x
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Count(*) vs Count(1) - SQL Server
... the same plans.
Contrary to the popular opinion, in Oracle they do too.
SYS_GUID() in Oracle is quite computation intensive function.
In my test database, t_even is a table with 1,000,000 rows
This query:
SELECT COUNT(SYS_GUID())
FROM t_even
runs for 48 seconds, since the function needs ...
C++ convert hex string to signed integer
I want to convert a hex string to a 32 bit signed integer in C++.
9 Answers
9
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Check if Python Package is installed
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If you mean a python script, just do something like this:
Python 3.3+ use sys.modules and find_spec:
import importlib.util
import sys
# For illustrative purposes.
name = 'itertools'
if name in sys.modules:
print(f"{name!r} already in sys.modules")
elif (spec := importlib.util.find_spec(name))...
What are the differences between the threading and multiprocessing modules?
...cessing in general.
However, Python* has an added issue: There's a Global Interpreter Lock that prevents two threads in the same process from running Python code at the same time. This means that if you have 8 cores, and change your code to use 8 threads, it won't be able to use 800% CPU and run 8x...
Convert a string to int using sql query
How to convert a string to integer using SQL query on SQL Server 2005?
4 Answers
4
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In Python, using argparse, allow only positive integers
...method that decides this for you:
def check_positive(value):
ivalue = int(value)
if ivalue <= 0:
raise argparse.ArgumentTypeError("%s is an invalid positive int value" % value)
return ivalue
parser = argparse.ArgumentParser(...)
parser.add_argument('foo', type=check_positive...
How to convert a column number (e.g. 127) into an Excel column (e.g. AA)
How do you convert a numerical number to an Excel column name in C# without using automation getting the value directly from Excel.
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How to convert an IPv4 address into a integer in C#?
I'm looking for a function that will convert a standard IPv4 address into an Integer. Bonus points available for a function that will do the opposite.
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Convert floats to ints in Pandas?
...eed them to be displayed as integers, or, without comma. Is there a way to convert them to integers or not display the comma?
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