大约有 40,000 项符合查询结果（耗时：0.0422秒） [XML]
float64 with pandas to_csv
...mvent this problem, I recommend you create another CSV file which contains all figures as integers, for example multiplying by 100, 1000 or other factor which turns out to be convenient. Inside your application, read the CSV file as usual and you will get those integer figures back. Then convert tho...
Is it smart to replace boost::thread and boost::mutex with c++11 equivalents?
...ried explaining the quality of boost, then gave up after some time :( ). Smaller reason why I would like to do it is that I would like to learn c++11 features, because people will start writing code in it.
So:
...
Difference between method and function in Scala
..., no instance - with a method type. As mentioned above, a Method Value actually has a Function Type. A method type is a def declaration - everything about a def except its body.
Value Declarations and Definitions and Variable Declarations and Definitions are val and var declarations, including both...
Do declared properties require a corresponding instance variable?
...
In your interface, you can formally declare an instance variable between the braces, or via @property outside the braces, or both. Either way, they become attributes of the class. The difference is that if you declare @property, then you can implement usin...
C++ catching all exceptions
...
try{
// ...
} catch (...) {
// ...
}
will catch all C++ exceptions, but it should be considered bad design. You can use c++11's new current_exception mechanism, but if you don't have the ability to use c++11 (legacy code systems requiring a rewrite), then you have no name...
How to find the array index with a value?
...code marked as the correct answer but it seems that that code wont work in all versions of IE. This answer works in all versions of IE but I changed the code slightly: var arrayPosition = $.inArray( value, Array ); works perfectly
– James Blackburn
Dec 13 '13 ...
How do I find the install time and date of Windows?
...estion, but how can I find out (hopefully via an API/registry key) the install time and date of Windows?
19 Answers
...
Difference between JSON.stringify and JSON.parse
...pt object into JSON text and stores that JSON text in a string, eg:
var my_object = { key_1: "some text", key_2: true, key_3: 5 };
var object_as_string = JSON.stringify(my_object);
// "{"key_1":"some text","key_2":true,"key_3":5}"
typeof(object_as_string);
// "string"
JSON.parse turns a...
Temporarily disable auto_now / auto_now_add
...s:
# my model
class FooBar(models.Model):
title = models.CharField(max_length=255)
updated_at = models.DateTimeField(auto_now=True, auto_now_add=True)
# my tests
foo = FooBar.objects.get(pk=1)
# force a timestamp
lastweek = datetime.datetime.now() - datetime.timedelta(days=7)
FooBar.obj...
MySQL和MongoDB设计实例进行对比 - 大数据 & AI - 清泛网 - 专注C/C++及内核技术
...查询：
db.getCollection("mobiles").find({
"params": {
$all: [
{$elemMatch: {"name": "待机时间", "value": {$gt: 100}}},
{$elemMatch: {"name": "外观设计", "value": "直板"}}
]
}
});
注：查询中用到的$all，$elemMatch等高...