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Unique fields that allow nulls in Django
...pty string by providing your own customized model form for Foo with a clean_bar method that turns the empty string into None:
class FooForm(forms.ModelForm):
class Meta:
model = Foo
def clean_bar(self):
return self.cleaned_data['bar'] or None
class FooAdmin(admin.ModelAdmin...
django : using select_related and get_object_or_404 together
Is there any way of using get_object_or_404 and select_related together or any other way to achieve the result of using these two together(except from putting it in try/except)??
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Convert Dictionary to semicolon separated string in c#
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Edited according to comments.
– the_drow
Oct 6 '10 at 11:18
7
@Amittai, @the_dr...
Glorified classes in the Java language
... lot of different answers, so I thought it would be useful to collect them all (and add some):
Classes
AutoBoxing classes - the compiler only allows for specific classes
Class - has its own literals (int.class for instance). I would also add its generic typing without creating new instances.
Stri...
PHP session lost after redirect
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First, carry out these usual checks:
Make sure session_start(); is called before any sessions are being called. So a safe bet would be to put it at the beginning of your page, immediately after the opening <?php declaration before anything else. Also ensure there are no whitespaces/tabs be...
Why are dashes preferred for CSS selectors / HTML attributes?
...re separated with underscore and there were no stops.
Also, using hyphens allows you to take advantage of the |= attribute selector, which selects any element containing the text, optionally followed by a dash:
span[class|="em"] { font-style: italic; }
This would make the following HTML elements...
Delegates in swift?
...interface MyCustomClass: UIViewController <ClassIWantToUseDelegate>, allowing you to init/configure the viewcontroller, as well as call delegate methods on the subviews? Something similar to this?
– Mahmud Ahmad
Aug 11 '16 at 22:32
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Hide keyboard when scroll UITableView
...to our UITableViewController class
override func scrollViewDidScroll(_ scrollView: UIScrollView) {
if !tableView.isDecelerating {
view.endEditing(true)
}
}
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Liquibase lock - reasons?
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There is a built-in command in Liquibase called releaseLocks that would execute what @Adrian Ber answered but I think it is database agnostic.
– user1434769
Oct 26 '15 at 11:17
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How can the Euclidean distance be calculated with NumPy?
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There's a function for that in SciPy. It's called Euclidean.
Example:
from scipy.spatial import distance
a = (1, 2, 3)
b = (4, 5, 6)
dst = distance.euclidean(a, b)
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