大约有 45,000 项符合查询结果（耗时：0.0239秒） [XML]
How to add column if not exists on PostgreSQL?
...statement:
DO $$
BEGIN
BEGIN
ALTER TABLE <table_name> ADD COLUMN <column_name> <column_type>;
EXCEPTION
WHEN duplicate_column THEN RAISE NOTICE 'column <column_name> already exists in <table_name>.';
END;
END;
$$
...
Can you do a partial checkout with Subversion?
...inity for the leaf directories
'''
import os
import getpass
import pysvn
__author__ = "Karl Ostmo"
__date__ = "July 13, 2011"
# =============================================================================
# XXX The os.path.commonprefix() function does not behave as expected!
# See here: http://...
How to check BLAS/LAPACK linkage in NumPy and SciPy?
...
The method numpy.show_config() (or numpy.__config__.show()) outputs information about linkage gathered at build time. My output looks like this. I think it means I am using the BLAS/LAPACK that ships with Mac OS.
>>> import numpy as np...
'uint32_t' identifier not found error
...'s custom integer types to the types expected by C. For example:
typedef __int32 int32_t;
typedef unsigned __int32 uint32_t;
/* ... etc. ... */
Hope this helps!
share
|
improve this answer
...
Microbit 航向/方位信息 · App Inventor 2 中文网
...
Microbit Magnetometer：航向/方位信息
Microbit_Magnetometer 可以配置 BBC micro:bit 的板载磁力计，并通过适当的方法接收一个或多个磁力计样本。
更多链接：
下载 micro:bit 板载磁力计的示例项目。查看 micro:bit 板载磁力...
How to print the full traceback without halting the program?
...ve already pointed out the traceback module.
Please notice that with print_exc, in some corner cases, you will not obtain what you would expect. In Python 2.x:
import traceback
try:
raise TypeError("Oups!")
except Exception, err:
try:
raise TypeError("Again !?!")
except:
...
C++中判断文件、目录是否存在的几种方法 - C/C++ - 清泛网 - 专注C/C++及内核技术
...
if(fh == NULL)
{
printf("%s","can not open the file");
}
三、_access
当然C中还有一种方式是直接调用c的函数库。
就是函数 int _access(const char* path,int mode);
这个函数的功能十分强大。
可以看看msdn的详细介绍
#include <io.h>
#include ...
How do you test that a Python function throws an exception?
...t ahold of the actual Exception object thrown:
import unittest
def broken_function():
raise Exception('This is broken')
class MyTestCase(unittest.TestCase):
def test(self):
with self.assertRaises(Exception) as context:
broken_function()
self.assertTrue('This i...
setuptools: package data folder location
...or example, if I have a project layout like so:
project/
foo/
__init__.py
data/
resource1/
foo.txt
You can add a function to __init__.py to locate an absolute path to a data
file:
import os
_ROOT = os.path.abspath(os.path.dirname(__file__))
def g...
Looping through a hash, or using an array in PowerShell
... how:
$hash = @{
a = 1
b = 2
c = 3
}
$hash.Keys | % { "key = $_ , value = " + $hash.Item($_) }
Output:
key = c , value = 3
key = a , value = 1
key = b , value = 2
share
|
improve th...