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What do all of Scala's symbolic operators mean?
...ode has three automatic imports:
// Not necessarily in this order
import _root_.java.lang._ // _root_ denotes an absolute path
import _root_.scala._
import _root_.scala.Predef._
The first two only make classes and singleton objects available. The third one contains all implicit conversions a...
How do I check if a SQL Server text column is empty?
...
For MySQL the correct syntax is: SQL SELECT * FROM TABLE WHERE IFNULL(FIELD, '')=''
– Cláudio Silva
Jan 27 at 10:40
...
How to delete the contents of a folder?
...bolic links, should work on Windows as well.
import os
import shutil
for root, dirs, files in os.walk('/path/to/folder'):
for f in files:
os.unlink(os.path.join(root, f))
for d in dirs:
shutil.rmtree(os.path.join(root, d))
...
What is the string concatenation operator in Oracle?
...
CONCAT is also compatible with other DBMSes (at least MySQL and Postgres).
– lapo
Oct 13 '15 at 15:07
1
...
How to define custom configuration variables in rails
...
# config/initializers/load_config.rb
APP_CONFIG = YAML.load_file("#{Rails.root}/config/config.yml")[Rails.env]
# application.rb
if APP_CONFIG['perform_authentication']
# Do stuff
end
share
|
im...
Django rest framework nested self-referential objects
...ution works but the count output of my serializer is wrong. It only counts root nodes. Any ideas? It's the same with djangorestframework-recursive.
– Lucas Veiga
May 3 '17 at 1:29
...
How to check if a process id (PID) exists
...wo ways:
Lets start by looking for a specific application in my laptop:
[root@pinky:~]# ps fax | grep mozilla
3358 ? S 0:00 \_ /bin/sh /usr/lib/firefox-3.5/run-mozilla.sh /usr/lib/firefox-3.5/firefox
16198 pts/2 S+ 0:00 \_ grep mozilla
All examples now will look...
Sort points in clockwise order?
...
+1: No atan(), no square root, and even no divisions. This is a good example of computer graphics thinking. Cull off all the easy cases as soon as possible, and even in the hard cases, compute as little as possible to know the required answer.
...
Given two directory trees, how can I find out which files differ by content?
...les in subdirs, for example rsync --options /usr /bin /var /sbin /lib /old_root will effectively compare current root / (by specifying all subdirs in it) and /old_root (containing for example some older backup of /), which is something diff -r can't do. And if you assume that files with same size, ...
Android Whatsapp/Chat Examples [closed]
...roid, application makes
http request to a server, implemented in php and mysql, to
authenticate, to register and to get the other friends' status and
data, then it communicates with other applications in other devices by
socket interface.
EDIT : Just found this! Maybe it's not related to W...