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Best way to select random rows PostgreSQL
...ery:
SELECT count(*) AS ct -- optional
, min(id) AS min_id
, max(id) AS max_id
, max(id) - min(id) AS id_span
FROM big;
The only possibly expensive part is the count(*) (for huge tables). Given above specifications, you don't need it. An estimate will do just fine,...
In Python, how can you load YAML mappings as OrderedDicts?
...rary code this is a bad idea. Also, it doesn't directly work with yaml.safe_load().
Fortunately, the solution can be improved without much effort:
import yaml
from collections import OrderedDict
def ordered_load(stream, Loader=yaml.Loader, object_pairs_hook=OrderedDict):
class OrderedLoader(L...
Converting string from snake_case to CamelCase in Ruby
... you're using Rails, String#camelize is what you're looking for.
"active_record".camelize # => "ActiveRecord"
"active_record".camelize(:lower) # => "activeRecord"
If you want to get an actual class, you should use String#constantize on top of that.
"app_user".came...
Google maps API V3 - multiple markers on exact same spot
...nt.
google.maps.event.trigger(markerClusterer, 'clusterclick', this.cluster_);
var zoom = this.map_.getZoom();
var maxZoom = markerClusterer.getMaxZoom();
// if we have reached the maxZoom and there is more than 1 marker in this cluster
// use our onClick method to popup a list of options
if (zoom ...
MemoryCache does not obey memory limits in configuration
...tCurrentPressure()
{
int num = GC.CollectionCount(2);
SRef ref2 = this._sizedRef;
if ((num != this._gen2Count) && (ref2 != null))
{
this._gen2Count = num;
this._idx ^= 1;
this._cacheSizeSampleTimes[this._idx] = DateTime.UtcNow;
this._cacheSizeSamples[this._idx] = ref2...
python exception message capturing
...is no longer supported in python 3. Use the following instead.
try:
do_something()
except BaseException as e:
logger.error('Failed to do something: ' + str(e))
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What is the difference between AF_INET and PF_INET in socket programming?
What is the difference between AF_INET and PF_INET in socket programming?
7 Answers
7
...
Correct owner/group/permissions for Apache 2 site files/folders under Mac OS X?
... than owner can access content)
chmod go+x DIR (to allow "users" including _www to "enter" the dir)
sudo chgrp -R _www ~/my/web/root (all web content is now group _www)
chmod -R go-rwx ~/my/web/root (nobody other than owner can access web content)
chmod -R g+rx ~/my/web/root (all web content is now...
How do I parallelize a simple Python loop?
...tead:
pool = multiprocessing.Pool(4)
out1, out2, out3 = zip(*pool.map(calc_stuff, range(0, 10 * offset, offset)))
Note that this won't work in the interactive interpreter.
To avoid the usual FUD around the GIL: There wouldn't be any advantage to using threads for this example anyway. You want t...
mongo group query how to keep fields
...h group, you can try aggregating like:
db.test.aggregate({
$group: {
_id : '$name',
name : { $first: '$name' },
age : { $first: '$age' },
sex : { $first: '$sex' },
province : { $first: '$province' },
city : { $first: '$city' },
area : { $first: '$area' },
address : { $firs...