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django: BooleanField, how to set the default value to true?
...fields/#django.forms.Field.initial ) like
class MyForm(forms.Form):
my_field = forms.BooleanField(initial=True)
If you're using a ModelForm, you can set a default value on the model field ( https://docs.djangoproject.com/en/2.2/ref/models/fields/#default ), which will apply to the resulting M...
How to create a DataTable in C# and how to add rows?
...ma/structure, do:
dt.WriteXMLSchema("dtSchemaOrStructure.xml");
Additionally, you can also export your data:
dt.WriteXML("dtDataxml");
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Python error “ImportError: No module named”
Python is installed in a local directory.
28 Answers
28
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The order of elements in Dictionary
...when enumerating them:
foreach (KeyValuePair<string, string> kvp in _Dictionary.OrderBy(k => k.Value)) {
...
}
In framework 2.0 you would first have to put the items in a list in order to sort them:
List<KeyValuePair<string, string>> items = new List<KeyValuePair<str...
What's the pythonic way to use getters and setters?
...
Try this: Python Property
The sample code is:
class C(object):
def __init__(self):
self._x = None
@property
def x(self):
"""I'm the 'x' property."""
print("getter of x called")
return self._x
@x.setter
def x(self, value):
print("sette...
Why doesn't GCC optimize a*a*a*a*a*a to (a*a*a)*(a*a*a)?
...scientific application. One thing I noticed is that GCC will optimize the call pow(a,2) by compiling it into a*a , but the call pow(a,6) is not optimized and will actually call the library function pow , which greatly slows down the performance. (In contrast, Intel C++ Compiler , executable ...
一个宏命令，就可以程序崩溃时生成dump文件 - C/C++ - 清泛网 - 专注C/C++及内核技术
...pFile
{
void CreateDumpFile(LPCWSTR lpstrDumpFilePathName, EXCEPTION_POINTERS *pException)
{
// 创建Dump文件
//
HANDLE hDumpFile = CreateFile(lpstrDumpFilePathName, GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
//...
C++ 通过主机名/域名获取IP - C/C++ - 清泛网 - 专注C/C++及内核技术
...2.h> 该头文件定义了Socket编程的功能 #pragma comment(lib,"ws2_32.lib") 连接ws2_32.lib库...代码如下：
#include <winsock2.h> //该头文件定义了Socket编程的功能
#pragma comment(lib,"ws2_32.lib") //连接ws2_32.lib库.只要程序中用到Winsock API 函数，...
Get object by id()? [duplicate]
...
@HamidFzM No, not really. If I have an ID, I maybe don't even know whether the object still exists or not.
– glglgl
Jul 21 '14 at 8:13
...
MongoDB仿关系型数据库Group聚合例子 - 大数据 & AI - 清泛网 - 专注C/C++及内核技术
...数据
Dictionary dic = new Dictionary();
dic["_userName"] = ""; // 与原字段名区分开
dic["_date"] = "";
dic["_data"] = "0";
MongoServer server = new MongoClient(MongoConnStr).GetServer();
MongoDatabase db = serve...