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How to set a Django model field's default value to a function call / callable (e.g., a date relative
...datetime, timedelta
class MyModel(models.Model):
# default to 1 day from now
my_date = models.DateTimeField(default=datetime.now() + timedelta(days=1))
This last line is not defining a function; it is invoking a function to create a field in the class.
PRE Django 1.7
Django lets you pass a ...
MFC Grid control 2.27 - C/C++ - 清泛网移动版 - 专注C/C++及内核技术
... Protected overridable functions
Clipboard
Sorting
Virtual Mode
Acknowledgements
General appearance and features
Files
Construction
Number of rows and columns
Sizing and position functions
Reordering rows and columns
Cell Editing and Validation
Structu...
Cleanest way to write retry logic?
... }
throw new AggregateException(exceptions);
}
}
You can now use this utility method to perform retry logic:
Retry.Do(() => SomeFunctionThatCanFail(), TimeSpan.FromSeconds(1));
or:
Retry.Do(SomeFunctionThatCanFail, TimeSpan.FromSeconds(1));
or:
int result = Retry.Do(SomeF...
Get current date/time in seconds
...
Date.now()
gives milliseconds since epoch. No need to use new.
Check out the reference here: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/now
(Not supported in IE8.)
...
Run a callback only if an attribute has changed in Rails
...saving to the database, or within the before_save filter:
changes should now be changes_to_save
changed? should now be has_changes_to_save?
changed should now be changed_attribute_names_to_save
<attribute>_change should now be <attribute>_change_to_be_saved
<attribute>_changed? s...
Is DateTime.Now the best way to measure a function's performance?
... existence of high-precision timers.
It is worth mentioning that DateTime.Now often is quite a bit slower than DateTime.UtcNow due to the work that has to be done with timezones, DST and such.
DateTime.UtcNow typically has a resolution of 15 ms. See John Chapman's blog post about DateTime.Now pre...
How can I find the length of a number?
...ake its absolute value and adjust the sign afterwards.
Update for ES2015
Now that Math.log10 is a thing, you can simply write
const len = Math.ceil(Math.log10(num + 1));
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Unknown provider: $modalProvider
...aven't created or included that dependency.
In this case, $modal isn't a known service. It sounds like you didn't pass in ui-bootstrap as a dependency when bootstrapping angular. angular.module('myModule', ['ui.bootstrap']); Also, be sure you are using the latest version of ui-bootstrap (0.6.0), ju...
Is there a stopwatch in Java?
...
Now you use this to get the milliseconds: long stopWatch = stopWatch.elapsed(TimeUnit.MILLISECONDS);
– PHPGuru
Mar 14 '18 at 17:41
...
Python strftime - date without leading 0?
...>>> '{dt.year}/{dt.month}/{dt.day}'.format(dt = datetime.datetime.now())
'2013/4/19'
Though perhaps beyond the scope of the original question, for more interesting formats, you can do stuff like:
>>> '{dt:%A} {dt:%B} {dt.day}, {dt.year}'.format(dt=datetime.datetime.now())
'Wedne...