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Why are Subjects not recommended in .NET Reactive Extensions?
...c class MessageListener
{
private readonly IObservable<IMessage> _messages;
private readonly IScheduler _scheduler;
public MessageListener()
{
_scheduler = new EventLoopScheduler();
var messages = ListenToMessages()
.Subscri...
How do you find the row count for all your tables in Postgres
...t executes. You could automate this to run against every table in the database, but you probably don't need that level of accuracy or want to wait that long.
The second approach notes that the statistics collector tracks roughly how many rows are "live" (not deleted or obsoleted by later updates) ...
Read each line of txt file to new array element
...sing, this should do what you're looking for
$lines = file($filename, FILE_IGNORE_NEW_LINES);
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How to print a groupby object
...
Simply do:
grouped_df = df.groupby('A')
for key, item in grouped_df:
print(grouped_df.get_group(key), "\n\n")
This also works,
grouped_df = df.groupby('A')
gb = grouped_df.groups
for key, values in gb.iteritems():
print(df.ix[...
SQL selecting rows by most recent date
... you would get an extra row returned. Which is the desired result based on his requirements.
– Carlton Jenke
Oct 9 '08 at 21:18
1
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What is the proper way to re-throw an exception in C#? [duplicate]
...n("Not enough room in array to copy elements starting at index given.");
_innerList.CopyTo(array, arrayIndex);
}
That's not the worse code because it's boilerplate and we can probably just copy it from some other implementation of CopyTo where it wasn't a simple pass-through and we had to implem...
Simplest way to profile a PHP script
...e, which I haven't tried yet. Seriously, isn't there a modern, updated CLI-based profiling tool for PHP that installs with Homebrew, requires minimal setup and gives easily human-readable output?
– forthrin
Aug 29 '16 at 6:38
...
find vs find_by vs where
...d are usually replaced with things like this:
Model.all
Model.first
find_by is used as a helper when you're searching for information within a column, and it maps to such with naming conventions. For instance, if you have a column named name in your database, you'd use the following syntax:
Mod...
Memoization in Haskell?
...alling, for example: fix f 123 = 144
We could memoize this by defining:
f_list :: [Int]
f_list = map (f faster_f) [0..]
faster_f :: Int -> Int
faster_f n = f_list !! n
That performs passably well, and replaces what was going to take O(n^3) time with something that memoizes the intermediate r...
iOS start Background Thread
...ou'd probably be better off using Grand Central Dispatch, though:
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
[self getResultSetFromDB:docids];
});
GCD is a newer technology, and is more efficient in terms of memory overhead and lines of code.
Updated w...