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Run a single migration file
...f the ruby file:
rails console
>> require "db/migrate/20090408054532_add_foos.rb"
>> AddFoos.up
Note: newer versions of rails may require AddFoos.new.up rather than AddFoos.up.
An alternative way (without IRB) which relies on the fact that require returns an array of class names:
sc...
How do you know when to use fold-left and when to use fold-right?
...ee it. It's "haskell-style pseudocode". :)
– laughing_man
Apr 21 '15 at 2:38
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Why use 'virtual' for class properties in Entity Framework model definitions?
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It allows the Entity Framework to create a proxy around the virtual property so that the property can support lazy loading and more efficient change tracking. See What effect(s) can the virtual keyword have in Entity Framework 4...
What is exactly the base pointer and stack pointer? To what do they point?
Using this example coming from wikipedia, in which DrawSquare() calls DrawLine(),
8 Answers
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Parse email content from quoted reply
...il from any quoted reply text that it might include. I've noticed that usually email clients will put an "On such and such date so and so wrote" or prefix the lines with an angle bracket. Unfortunately, not everyone does this. Does anyone have any idea on how to programmatically detect reply text...
Format a datetime into a string with milliseconds
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Useful with timezone too: date = datetime(2019,5,10) date_with_tz = pytz.timezone('Europe/Rome').localize(date) date_with_tz.isoformat(sep='T', timespec='milliseconds') output: '2019-05-10T00:00:00.000+02:00'
– Ena
May 10 '19 at 9:17
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Will strlen be calculated multiple times if used in a loop condition?
...optimiser might be able to deduce that the value won't change, but I personally wouldn't rely on that.
I'd do something like
for (int i = 0, n = strlen(ss); i < n; ++i)
or possibly
for (int i = 0; ss[i]; ++i)
as long as the string isn't going to change length during the iteration. If it mi...
Getting current device language in iOS?
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The solutions provided will actually return the current region of the device - not the currently selected language. These are often one and the same. However, if I am in North America and I set my language to Japanese, my region will still be English (Unite...
SQL Server indexes - ascending or descending, what difference does it make?
...ces to rows.
Since the table is clustered, the references to rows are actually the values of the pk. They are also ordered within each value of col1.
This means that that leaves of the index are actually ordered on (col1, pk), and this query:
SELECT col1, pk
FROM mytable
ORDER BY
col1...
How can I add an item to a SelectList in ASP.net MVC
Basically I am looking to insert an item at the beginning of a SelectList with the default value of 0 and the Text Value of " -- Select One --"
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