Creating the class to be the subject of the Mirror
class Project {
var title: String = ""
var id: Int = 0
var platform: String = ""
var version: Int = 0
var info: String?
}
Creating an instance that will actually be the subject of the mirror. Also he...
Sometimes it's not a good practice expose an internal collection since it can lead to a malicious code vulnerability due to it's mutable characteristic. In order to provide "read-only" collections java provides its unmodifiable versions.
An unmodifiable collection is often a copy of a mod...
Consider the following tough-to-vectorize for loop, which creates a vector of length len where the first element is specified (first) and each element x_i is equal to cos(x_{i-1} + 1):
repeatedCosPlusOne <- function(first, len) {
x <- numeric(len)
x[1] <- first
for (i in 2:len) {
...
Let's create our own error type for this example.
2.2
enum CustomError: ErrorType {
case SomeError
case AnotherError
}
func throwing() throws {
throw CustomError.SomeError
}
3.0
enum CustomError: Error {
case someError
case anotherError
}
func throwing() thr...
In order to specify which version of python the Linux shell should use the first line of Python scripts can be a shebang line, which starts with #!:
#!/usr/bin/python
If you are in a virtual environment, then python myscript.py will use the Python from your virtual environment, but ./myscript.py...
To help to maintain clean code, Rails follows the principle of DRY.
It involves whenever possible, re-using as much code as possible rather than duplicating similar code in multiple places (for example, using partials). This reduces errors, keeps your code clean and enforces the principle of writin...
In Rails, you find yourself looking at controllers, views, and models for your database.
To reduce the need for heavy configuration, Rails implements rules to ease up working with the application. You may define your own rules but for the beginning (and for later on) it's a good idea to stick to co...
By default, the various Collection types are not thread-safe.
However, it's fairly easy to make a collection thread-safe.
List<String> threadSafeList = Collections.synchronizedList(new ArrayList<String>());
Set<String> threadSafeSet = Collections.synchronizedSet(new HashSet<S...
The default value for an enum is zero. If an enum does not define an item with a value of zero, its default value will be zero.
public class Program
{
enum EnumExample
{
one = 1,
two = 2
}
public void Main()
{
var e =...
Now that the router is configured and our app knows how to handle the routes, we need to show the actual components that we configured.
To do so, configure your HTML template/file for your top-level (app) component like so:
//app.ts
import {Component} from '@angular/core';
import {Router, ROUT...
git cherry-pick <commit-A>..<commit-B> will place every commit after A and up to and including B on top of the currently checked-out branch.
git cherry-pick <commit-A>^..<commit-B> will place commit A and every commit up to and including B on top of the currently checked-out...
The @import CSS at-rule is used to import style rules from other style sheets. These rules must precede all other types of rules, except @charset rules; as it is not a nested statement, @import cannot be used inside conditional group at-rules.
@import.
How to use @import
You can use @import rule ...
Declaring a variable const only prevents its value from being replaced by a new value. const does not put any restrictions on the internal state of an object. The following example shows that a value of a property of a const object can be changed, and even new properties can be added, because the ob...
General syntax
git push <remotename> <object>:<remotebranchname>
Example
git push origin master:wip-yourname
Will push your master branch to the wip-yourname branch of origin (most of the time, the repository you cloned from).
Delete remote branch
Deleting the remote br...
In all versions of Python, we can represent infinity and NaN ("not a number") as follows:
pos_inf = float('inf') # positive infinity
neg_inf = float('-inf') # negative infinity
not_a_num = float('nan') # NaN ("not a number")
In Python 3.5 and higher, we can also us...
Vue.js allows you to append optional “filters” to the end of an expression, denoted by the “pipe” symbol:
{{ message | capitalize }}
Here we are “piping” the value of the message expression through the built-in capitalize filter, which is in fact just a JavaScript function that returns the capit...
Files opened in a non-binary mode (e.g. 'r' or 'w') deal with strings. The deafult encoding is 'utf8'.
open(fn, mode='r') # opens file for reading in utf8
open(fn, mode='r', encoding='utf16') # opens file for reading utf16
# ERROR: cannot write bytes when a string is expecte...
Create a ModelForm from an existing Model class, by subclassing ModelForm:
from django import forms
class OrderForm(forms.ModelForm):
class Meta:
model = Order
fields = ['item', 'order_date', 'customer', 'status']
Writing a view to create object can be quite boring. You have to display a form, you have to validate it, you have to save the item or return the form with an error. Unless you use one of the generic editing views.
app/views.py
from django.core.urlresolvers import reverse_lazy
from django.views.g...
