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Rails: around_* callbacks
...classes/ActiveRecord/Callbacks.html , but don't understand when the around_* callbacks are triggered in relation to before_* and after_* .
...
In where shall I use isset() and !empty()
.....) contains some non-empty data.
To answer question 1 :
$str = '';
var_dump(isset($str));
gives
boolean true
Because the variable $str exists.
And question 2 :
You should use isset to determine whether a variable exists ; for instance, if you are getting some data as an array, you migh...
How to remove from a map while iterating it?
...begin(); it != m.cend() /* not hoisted */; /* no increment */)
{
if (must_delete)
{
m.erase(it++); // or "it = m.erase(it)" since C++11
}
else
{
++it;
}
}
Note that we really want an ordinary for loop here, since we are modifying the container itself. The range-based loop sh...
How to replace multiple strings in a file using PowerShell
... PowerShell to continue parsing the expression on the next line:
$original_file = 'path\filename.abc'
$destination_file = 'path\filename.abc.new'
(Get-Content $original_file) | Foreach-Object {
$_ -replace 'something1', 'something1aa' `
-replace 'something2', 'something2bb' `
-re...
Git Symlinks in Windows
... on Windows
git config --global alias.add-symlink '!'"$(cat <<'ETX'
__git_add_symlink() {
if [ $# -ne 2 ] || [ "$1" = "-h" ]; then
printf '%b\n' \
'usage: git add-symlink <source_file_or_dir> <target_symlink>\n' \
'Create a symlink in a git repository on a Wi...
Mongoose query where value is not null
...ry The up-to-date doc about it, is here: mongoosejs.com/docs/api.html#query_Query-ne
– zeropaper
Jul 20 '14 at 7:52
Ho...
Converting a Java collection into a Scala collection
... but you can also avoid using jcl.Buffer:
Set(javaApi.query(...).toArray: _*)
Note that scala.collection.immutable.Set is made available by default thanks to Predef.scala.
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Installing python module within code
...upported by pip. Furthermore since pip v10, all code has been moved to pip._internal precisely in order to make it clear to users that programmatic use of pip is not allowed.
Use sys.executable to ensure that you will call the same pip associated with the current runtime.
import subprocess
import ...
What is an 'endpoint' in Flask?
...c view is defined like this:
@app.route('/greeting/<name>')
def give_greeting(name):
return 'Hello, {0}!'.format(name)
Note that the function you referred to (add_url_rule) achieves the same goal, just without using the decorator notation. Therefore, the following is the same:
# No "ro...
Why do we always prefer using parameters in SQL statements?
... the SQL statement is not going to be the same
– marc_s
Sep 21 '11 at 20:57
1
that means sql inje...