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How to upload a file in Django? [closed]
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Phew, Django documentation really does not have good example about this. I spent over 2 hours to dig up all the pieces to understand how this works. With that knowledge I implemented a project that makes possible to upload files and show them as list. To...
WITH CHECK ADD CONSTRAINT followed by CHECK CONSTRAINT vs. ADD CONSTRAINT
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It doesn't look like WITH CHECK is actually the default, it's only the default for new data. From msdn.microsoft.com/en-us/library/ms190273.aspx: "If not specified, WITH CHECK is assumed for new constraints, and WITH NOCHECK is assumed for re-enabled constraints."...
str performance in python
...; import dis
>>> dis.dis(lambda: str(100000))
8 0 LOAD_GLOBAL 0 (str)
3 LOAD_CONST 1 (100000)
6 CALL_FUNCTION 1
9 RETURN_VALUE
>>> dis.dis(lambda: '%s' % 100000)
9 0 LOAD...
How does python numpy.where() work?
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How do they achieve internally that you are able to pass something like x > 5 into a method?
The short answer is that they don't.
Any sort of logical operation on a numpy array returns a boolean array. (i.e. __gt__, __lt__, etc all return boolea...
How to export all data from table to an insertable sql format?
I have a Table (call it A_table ) in a database (call it A_db ) in Microsoft SQL Server Management Studio, and there are 10 rows.
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How can I use a DLL file from Python?
...hlapi32.dll")
# Set up prototype and parameters for the desired function call.
# HLLAPI
hllApiProto = ctypes.WINFUNCTYPE (
ctypes.c_int, # Return type.
ctypes.c_void_p, # Parameters 1 ...
ctypes.c_void_p,
ctypes.c_void_p,
ctypes.c_void_p) # ... thru 4.
hllApiParams = (...
CPU指令集avx程序无法运行，运行崩溃 - C/C++ - 清泛网 - 专注C/C++及内核技术
CPU指令集avx程序无法运行，运行崩溃cpu_avx_run原因就是CPU不支持相应的指令集导致的。Linux上使用 lscpu 命令查看CPU指令集，看是否支持。比如_mm256_cmpeq_epi64 这个函数需要avx2指令集，但是CPU不支持，就导致程序崩溃起不来。原因...
Argparse optional positional arguments?
I have a script which is meant to be used like this:
usage: installer.py dir [-h] [-v]
3 Answers
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Difference between objectForKey and valueForKey?
...ex).
valueForKey: is a KVC method. It works with ANY class. valueForKey: allows you to access a property using a string for its name. So for instance, if I have an Account class with a property accountNumber, I can do the following:
NSNumber *anAccountNumber = [NSNumber numberWithInt:12345];
Acco...
What is the best algorithm for overriding GetHashCode?
...hroughout the .NET base class libraries. Implementing it properly is especially important to find items quickly in a collection or when determining equality.
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