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Node.js Mongoose.js string to ObjectId function
...n it is saved from a string, mongo tells me it is still just a string. The _id of the object, for instance, is displayed as objectId("blah") .
...
What is the use of static variable in C#? When to use it? Why can't I declare the static variable in
...red. Let me explain this with an example:
class circle
{
public float _PI =3.14F;
public int Radius;
public funtionArea(int radius)
{
return this.radius * this._PI
}
}
class program
{
public static void main()
{
Circle c1 = new Cirle();
flo...
How to pull a random record using Django's ORM?
...
Using order_by('?') will kill the db server on the second day in production. A better way is something like what is described in Getting a random row from a relational database.
from django.db.models.aggregates import Count
from random...
Difference between abstract class and interface in Python
... NotImplementedError("Class %s doesn't implement aMethod()" % (self.__class__.__name__)) is more informative error message :)
– naught101
Sep 3 '14 at 1:43
9
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How to get instance variables in Python?
...
Every object has a __dict__ variable containing all the variables and its values in it.
Try this
>>> hi_obj = hi()
>>> hi_obj.__dict__.keys()
share...
Use of 'prototype' vs. 'this' in JavaScript?
...hich can be accessed with Object.getPrototypeOf(myObject) or with myObject.__proto__ in some browsers. The proto property indicates the object's parent in the prototype chain (or the object from which this object inherits). The prototype property (which is only on functions) indicated the object t...
SQL Server: Filter output of sp_who2
Under SQL Server, is there an easy way to filter the output of sp_who2? Say I wanted to just show rows for a certain database, for example.
...
How do I bind a WPF DataGrid to a variable number of columns?
...c readonly Dictionary<DataGrid, NotifyCollectionChangedEventHandler> _handlers;
static DataGridColumnsBehavior()
{
_handlers = new Dictionary<DataGrid, NotifyCollectionChangedEventHandler>();
}
private static void BindableColumnsPropertyChanged(DependencyObject ...
How to profile a bash shell script slow startup?
...
PS4='+ $EPOCHREALTIME\011 '
As pointed out by @pawamoy, you can use BASH_XTRACEFD to send the output of the trace to a separate file descriptor if you have Bash 4.1 or later. From this answer:
#!/bin/bash
exec 5> command.txt
BASH_XTRACEFD="5"
echo -n "hello "
set -x
echo -n world
set +x
e...
How to check if a file exists in Go?
...doesn't exist, equivalent to Python's if not os.path.exists(filename):
if _, err := os.Stat("/path/to/whatever"); os.IsNotExist(err) {
// path/to/whatever does not exist
}
To check if a file exists, equivalent to Python's if os.path.exists(filename):
Edited: per recent comments
if _, err := o...