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Django auto_now and auto_now_add
...cts I have written using Django, and so your save() would look like this:
from django.utils import timezone
class User(models.Model):
created = models.DateTimeField(editable=False)
modified = models.DateTimeField()
def save(self, *args, **kwargs):
''' On save, update ti...
Animate change of view background color on Android
...
You can use new Property Animation Api for color animation:
int colorFrom = getResources().getColor(R.color.red);
int colorTo = getResources().getColor(R.color.blue);
ValueAnimator colorAnimation = ValueAnimator.ofObject(new ArgbEvaluator(), colorFrom, colorTo);
colorAnimation.setDuration(250)...
how to convert binary string to decimal?
...ave misunderstood what the parseInt. I thought it would convert the string from base 10 -> whatever (thinking like parseInt('5612', 2) would return its binary form ;).
– srph
Mar 17 '15 at 13:54
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Why use Dijkstra's Algorithm if Breadth First Search (BFS) can do the same thing faster?
Both can be used to find the shortest path from single source. BFS runs in O(E+V) , while Dijkstra's runs in O((V+E)*log(V)) .
...
RE error: illegal byte sequence on Mac OS X
...s on demand:
Standard utility iconv can be used to convert to (-t) and/or from (-f) encodings; iconv -l lists all supported ones.
Examples:
Convert FROM ISO-8859-1 to the encoding in effect in the shell (based on LC_CTYPE, which is UTF-8-based by default), building on the above example:
# Conv...
Async/await vs BackgroundWorker
...ow, you could use TPL instead:
var synchronizationContext = TaskScheduler.FromCurrentSynchronizationContext();
Task.Factory.StartNew(() =>
{
int i = 0;
// simulate lengthy operation
Stopwatch sw = Stopw...
How to try convert a string to a Guid [duplicate]
...er something by Guid (since its primary key in a table) what will you send from the front in a request? Most likely a string in URL, but on back in the controller you would most like wanna use it as Guid. As for speed comparison: stackoverflow.com/questions/713109/…
– DanteTh...
The cause of “bad magic number” error when loading a workspace and how to avoid it?
...
Also worth noting the following from a document by the R Core Team summarizing changes in versions of R after v3.5.0 (here):
R has new serialization format (version 3) which supports custom serialization of
ALTREP framework objects... Serialized data in fo...
What is a “callback” in C and how are they implemented?
From the reading that I have done, Core Audio relies heavily on callbacks (and C++, but that's another story).
9 Answers
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The way to check a HDFS directory's size?
...iles. Without the -s option, the calculation is done by going 1-level deep from the given path.
The -h option will format file sizes in a human-readable fashion (e.g 64.0m instead of 67108864)
The -v option will display the names of columns as a header line.
The -x option will exclude snapshots from...