HTTP 404 Not Found means that the server couldn't find the path using the URI that the client requested.
HTTP/1.1 404 Not Found
Most often, the requested file was deleted, but sometimes it can be a document root misconfiguration or a lack of permissions (though missing permissions more frequentl...
Use 403 Forbidden when a client has requested a resource that is inaccessible due to existing access controls. For example, if your app has an /admin route that should only be accessible to users with administrative rights, you can use 403 when a normal user requests the page.
GET /admin HTTP/1.1
...
s = {1, 2, 3}
# get every element in s
for a in s:
print a # prints 1, then 2, then 3
# copy into list
l1 = list(s) # l1 = [1, 2, 3]
# use list comprehension
l2 = [a * 2 for a in s if a > 2] # l2 = [6]
Use unpacking to extract the first element and ensure it's the only one:
a, = iterable
def foo():
yield 1
a, = foo() # a = 1
nums = [1, 2, 3]
a, = nums # ValueError: too many values to unpack
Start with iter() built-in to get iterator over iterable and use next() to get elements one by one until StopIteration is raised signifying the end:
s = {1, 2} # or list or generator or even iterator
i = iter(s) # get iterator
a = next(i) # a = 1
b = next(i) # b = 2
c = next(i) # raises S...
def gen():
yield 1
iterable = gen()
for a in iterable:
print a
# What was the first item of iterable? No way to get it now.
# Only to get a new iterator
gen()
You can write the default protocol implementation for a specific class.
protocol MyProtocol {
func doSomething()
}
extension MyProtocol where Self: UIViewController {
func doSomething() {
print("UIViewController default protocol implementation")
}
}
class M...
Setting up
settings.py
from django.utils.translation import ugettext_lazy as _
USE_I18N = True # Enable Internationalization
LANGUAGE_CODE = 'en' # Language in which original texts are written
LANGUAGES = [ # Available languages
('en', _("English")),
('de', _("Germ...
In order to efficiently handle cycle detection, we consider each node as part of a tree. When adding an edge, we check if its two component nodes are part of distinct trees. Initially, each node makes up a one-node tree.
algorithm kruskalMST'(G: a graph)
sort G's edges by their value
MST ...
The above forest methodology is actually a disjoint-set data structure, which involves three main operations:
subalgo makeSet(v: a node):
v.parent = v <- make a new tree rooted at v
subalgo findSet(v: a node):
if v.parent == v:
return v
return findSet(v.parent...
We can do two things to improve the simple and sub-optimal disjoint-set subalgorithms:
Path compression heuristic: findSet does not need to ever handle a tree with height bigger than 2. If it ends up iterating such a tree, it can link the lower nodes directly to the root, optimizing future trav...
Sort the edges by value and add each one to the MST in sorted order, if it doesn't create a cycle.
algorithm kruskalMST(G: a graph)
sort G's edges by their value
MST = an empty graph
for each edge e in G:
if adding e to MST does not create a cycle:
add e to MST
...
ceil()
The ceil() method rounds a number upwards to the nearest integer, and returns the result.
Syntax:
Math.ceil(n);
Example:
console.log(Math.ceil(0.60)); // 1
console.log(Math.ceil(0.40)); // 1
console.log(Math.ceil(5.1)); // 6
console.log(Math.ceil(-5.1)); // -5
console.log(Math....
You can calculate a number in the Fibonacci sequence using recursion.
Following the math theory of F(n) = F(n-2) + F(n-1), for any i > 0,
// Returns the i'th Fibonacci number
public int fib(int i) {
if(i <= 2) {
// Base case of the recursive function.
// i is either 1...
JSON stands for "JavaScript Object Notation", but it's not JavaScript. Think of it as just a data serialization format that happens to be directly usable as a JavaScript literal. However, it is not advisable to directly run (i.e. through eval()) JSON that is fetched from an external source...
1. Target a device by serial number
Use the -s option followed by a device name to select on which device the adb command should run.
The -s options should be first in line, before the command.
adb -s <device> <command>
Example:
adb devices
List of devices attached
emulator-55...
HTML also provides the tables with the <thead>, <tbody>, <tfoot>, and <caption> elements. These additional elements are useful for adding semantic value to your tables and for providing a place for separate CSS styling.
When printing out a table that doesn't fit onto one (pa...
var user = Sitecore.Security.Accounts.User.FromName("sitecore/testname", false);
using (new Sitecore.Security.Accounts.UserSwitcher(user))
{
var item = Sitecore.Context.Database.GetItem("/sitecore/content/home");
}
