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Function in JavaScript that can be called only once
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If by "won't be executed" you mean "will do nothing when called more than once", you can create a closure:
var something = (function() {
var executed = false;
return function() {
if (!executed) {
executed = true;
// do something
}
...
How do I get logs/details of ansible-playbook module executions?
...dd the following lines to your ansible configuration file:
[defaults]
log_path=/path/to/logfile
Ansible will look in several places for the config file:
ansible.cfg in the current directory where you ran ansible-playbook
~/.ansible.cfg
/etc/ansible/ansible.cfg
...
SQL Server Insert if not exists
...ode
BEGIN
INSERT INTO EmailsRecebidos (De, Assunto, Data)
VALUES (@_DE, @_ASSUNTO, @_DATA)
WHERE NOT EXISTS ( SELECT * FROM EmailsRecebidos
WHERE De = @_DE
AND Assunto = @_ASSUNTO
AND Data = @_DATA);
END
replace with
BEGIN
I...
How to create Java gradle project
...ted to the gradle project. Then, how can I set the source folders automatically?
– verystrongjoe
May 15 '15 at 0:26
On...
Create list of single item repeated N times
I want to create a series of lists, all of varying lengths. Each list will contain the same element e , repeated n times (where n = length of the list).
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Numpy: find first index of value fast
...ments it. If you use anaconda python distribution it should already be installed.
The code will be compiled so it will be fast.
@jit(nopython=True)
def find_first(item, vec):
"""return the index of the first occurence of item in vec"""
for i in xrange(len(vec)):
if item == vec[i]:
...
Is it a good practice to use an empty URL for a HTML form's action attribute? (action=“”)
...for compatibility with legacy content. [RFC3986]
This definitely works in all current browsers, but may not work as expected in some older browsers ("browsers do weird things with an empty action="" attribute"), which is why the spec strongly discourages authors from leaving it empty:
The action a...
How do I get around type erasure on Scala? Or, why can't I get the type parameter of my collections?
...hese instances are objects, you can pass them around, store them, and generally call methods on them. With the support of implicit parameters, it becomes a very powerful tool. Take the following example, for instance:
object Registry {
import scala.reflect.Manifest
private var map= Map.empty[...
How do I get the base URL with PHP?
... XAMPP on Windows Vista. In my development, I have http://127.0.0.1/test_website/ .
22 Answers
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When saving, how can you check if a field has changed?
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Essentially, you want to override the __init__ method of models.Model so that you keep a copy of the original value. This makes it so that you don't have to do another DB lookup (which is always a good thing).
class Person(models.Model):
name = models.CharF...