大约有 40,000 项符合查询结果（耗时：0.0528秒） [XML]
How to convert linq results to HashSet or HashedSet
...f T explicitly:
var query = from i in Enumerable.Range(0, 10)
select new { i, j = i + 1 };
var resultSet = query.ToHashSet();
You can't do that with an explicit call to the HashSet<T> constructor. We're relying on type inference for generic methods to do it for us.
Now you coul...
Vagrant stuck connection timeout retrying
... the GUI of Virtual box to see that it was waiting for input on startup to select whether I wanted to boot directly to ubuntu or safemode etc.
To turn on the GUI you have to put this in your vagrant config Vagrantfile:
config.vm.provider :virtualbox do |vb|
vb.gui = true
end
...
Faster s3 bucket duplication
...
If you don't mind using the AWS console, you can:
Select all of the files/folders in the first bucket
Click Actions > Copy
Create a new bucket and select it
Click Actions > Paste
It's still fairly slow, but you can leave it alone and let it do its thing.
...
How to retrieve the current version of a MySQL database management system (DBMS)?
... and Windows.
When connected to a MySQL server with a client you can use
select version()
or
select @@version
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How to pull a random record using Django's ORM?
...on't know about other databases).
order_by('?')[:N] will be translated to SELECT ... FROM ... WHERE ... ORDER BY RAND() LIMIT N query.
It means that for every row in table the RAND() function will be executed, then the whole table will be sorted according to value of this function and then first N...
Frequency table for a single variable
... the columns as such
[my_series[c].value_counts() for c in list(my_series.select_dtypes(include=['O']).columns)]
Breakdown:
my_series.select_dtypes(include=['O'])
Selects just the categorical data
list(my_series.select_dtypes(include=['O']).columns)
Turns the columns f...
android get all contacts
... ContactsContract.Contacts.DISPLAY_NAME
} ;
String selection = null; //Selection criteria
String[] selectionArgs = {}; //Selection criteria
String sortOrder = null; //T...
Hiding the scroll bar on an HTML page
... /* 7 */
These can each be combined with additional pseudo-selectors:
:horizontal – The horizontal pseudo-class applies to any scrollbar pieces that have a horizontal orientation.
:vertical – The vertical pseudo-class applies to any scrollbar pieces that have a vertical orienta...
reformat in vim for a nice column layout
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Great tip! Just adding, it works for visual selection too with :'<,'>!column -t
– freitass
Aug 23 '12 at 13:16
2
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LINQ-to-SQL vs stored procedures? [closed]
... I cannot get over the performance deficit that is introduced by having to select data out of the database in order to update it (Attach() is also possible, but it's rather poopey)
– Ed James
Mar 2 '10 at 15:46
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