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form_for with nested resources
... at http://edgeguides.rubyonrails.org/routing.html#creating-paths-and-urls-from-objects
For example, inside a collections partial with comment_item supplied for iteration,
<%= link_to "delete", article_comment_path(@article, comment_item),
:method => :delete, :confirm => "Really?" %...
How do I clone a Django model instance object and save it to the database?
...objects one by one. If you don't want the call to the database, just do:
from copy import deepcopy
new_instance = deepcopy(object_you_want_copied)
new_instance.id = None
new_instance.save()
It does the same thing as some of these other answers, but it doesn't make the database call to retrieve ...
Convert datetime to Unix timestamp and convert it back in python
...f your original naive datetime was UTC, the way to recover it is to use utcfromtimestamp instead of fromtimestamp.
On the other hand, if your original naive datetime was local, you shouldn't have subtracted a UTC timestamp from it in the first place; use datetime.fromtimestamp(0) instead.
Or, if y...
Type-juggling and (strict) greater/lesser-than comparisons in PHP
...
PHP's comparison operators deviate from the computer-scientific definitions in several ways:
In order to constitute an equivalence relation == has to be reflexive, symmetric and transitive:
PHP's == operator is not reflexive, i.e. $a == $a is not always tru...
Why does ConcurrentHashMap prevent null keys and values?
...
From the author of ConcurrentHashMap himself (Doug Lea):
The main reason that nulls aren't allowed in ConcurrentMaps
(ConcurrentHashMaps, ConcurrentSkipListMaps) is that ambiguities that
may be just barely tolerable i...
Are there disadvantages to using a generic varchar(255) for all text-based fields?
...uestion with MySQL, I'll mention a MySQL-specific tip: as rows are copied from the storage engine layer to the SQL layer, VARCHAR fields are converted to CHAR to gain the advantage of working with fixed-width rows. So the strings in memory become padded out to the maximum length of your declared V...
std::cin input with spaces?
...change one line instead of two lines. Change 2 would be to test the return from cin.getline() by using, for example, if (!cin.getline(input, sizeof(input))) { ...handle EOF or error... } or something similar, to remind the OP that input operations, in particular, are vulnerable to unexpected behavio...
How do I debug an MPI program?
...ce Analysis Tool (STAT). We use this at Livermore to collect stack traces from potentially hundreds of thousands of running processes and to represent them intelligently to users. It's not a full-featured debugger (a full-featured debugger would never scale to 208k cores), but it will tell you whi...
Wait for page load in Selenium
...r> wait = new OpenQA.Selenium.Support.UI.WebDriverWait(driver, TimeSpan.FromSeconds(30.00));
wait.Until(driver1 => ((IJavaScriptExecutor)driver).ExecuteScript("return document.readyState").Equals("complete"));
share...
Can't connect to local MySQL server through socket '/tmp/mysql.sock
...nce all other access through the socket works fine, including other access from Python.
– Old Pro
May 11 '13 at 19:17
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