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Flatten nested dictionaries, compressing keys
...ng the dictionary at final step.
import collections
def flatten(d, parent_key='', sep='_'):
items = []
for k, v in d.items():
new_key = parent_key + sep + k if parent_key else k
if isinstance(v, collections.MutableMapping):
items.extend(flatten(v, new_key, sep=s...
MFC学习总结 (90个技巧) dlg 上建立View - C/C++ - 清泛网 - 专注C++内核技术
...框为 属性页的类(头文件)里创建CpropertySheet类的一个对象m_tabsheet和新创建的对话框类的对象m_skatch；最后，在.cpp 文件里的OnInitDialog()之类的函数里实现如下代码：
m_tabsheet.Create(this, WS_CHILD | WS_VISIBLE, 0);
//使选项卡的按钮在下...
MySQL: What's the difference between float and double?
...00002 | 1.6900000000 |
This is using MySQL 6.7
Query:
SELECT
float_1 + float_2 as 'float add',
double_1 + double_2 as 'double add',
decimal_1 + decimal_2 as 'decimal add',
float_1 * float_2 as 'float multiply',
double_1 * double_2 as 'double multiply',
decimal_1 * decim...
Django select only rows with duplicate field values
...values('name')
.annotate(Count('id'))
.order_by()
.filter(id__count__gt=1)
This is as close as you can get with Django. The problem is that this will return a ValuesQuerySet with only name and count. However, you can then use this to construct a regula...
capturing self strongly in this block is likely to lead to a retain cycle
...ng a weak reference to self before accessing timerDisp inside your block:
__weak typeof(self) weakSelf = self;
[player addPeriodicTimeObserverForInterval:CMTimeMakeWithSeconds(0.1, 100)
queue:nil
usingBlock:^(CMTime time) {
...
Get last result in interactive Python shell
...
Underscore.
>>> 5+5
10
>>> _
10
>>> _ + 5
15
>>> _
15
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OceanBase使用libeasy原理源码分析：服务器端 - 数据库(内核) - 清泛网 - ...
...、OceanBase启动时的使用模式
二、 基础数据结构
2.1 easy_list_t
2.2 easy_pool_t
2.3 easy_buf_t
2.4 easy_connection_t
三、 连接建立
四、 同步处理(OceanBase少量使用这种模式)
五、 异步处理(OceanBase大量采用这种模式)
六、 资源管理
...
How to make a cross-module variable?
The __debug__ variable is handy in part because it affects every module. If I want to create another variable that works the same way, how would I do it?
...
Pickle or json?
...ccf1b3fa91f4399902bb534/raw/03e8dbab11b5605bc572bc117c8ac34cfa959a70/pickle_vs_json.py
python pickle_vs_json.py
Results with python 2.7 on a decent 2015 Xeon processor:
Dir Entries Method Time Length
dump 10 JSON 0.017 1484510
load 10 JSON 0.375 -
dump 10 Pickle 0.011 ...
sql “LIKE” equivalent in django query
...
Use __contains or __icontains (case-insensitive):
result = table.objects.filter(string__contains='pattern')
The SQL equivalent is
SELECT ... WHERE string LIKE '%pattern%';
...