Tutorial by Examples: p

Presence works by sending messages when a user joins, leaves, or times out from a particular channel. You can listen for these messages to track who is in a channel, and how long since they did anything. First, make sure each user as a UUID. Set this when you initialize PubNub: var pubnub = PUBNUB...

In addition to .done, .fail and .always promise callbacks, which are triggered based on whether the request was successful or not, there is the option to trigger a function when a specific HTTP Status Code is returned from the server. This can be done using the statusCode parameter. $.ajax({ t...

For example, you can take the absolute value of each element: list(map(abs, (1, -1, 2, -2, 3, -3))) # the call to `list` is unnecessary in 2.x # Out: [1, 1, 2, 2, 3, 3] Anonymous function also support for mapping a list: map(lambda x:x*2, [1, 2, 3, 4, 5]) # Out: [2, 4, 6, 8, 10] or convert...

For example calculating the average of each i-th element of multiple iterables: def average(*args): return float(sum(args)) / len(args) # cast to float - only mandatory for python 2.x measurement1 = [100, 111, 99, 97] measurement2 = [102, 117, 91, 102] measurement3 = [104, 102, 95, 101] ...

Xcode projects are used to organize source files, library dependencies, and other resources, as well as the settings and steps required to build the project's products. Workspaces are groups of projects and other files. Create a project You can create a New Project (⇧⌘N) from a number of built-in ...

There are two ways of creating aliases in Git: with the ~/.gitconfig file: [alias] ci = commit st = status co = checkout with the command line: git config --global alias.ci "commit" git config --global alias.st "status" git config --global alias....

There is a complementary function for filter in the itertools-module: Python 2.x2.0.1 # not recommended in real use but keeps the example valid for python 2.x and python 3.x from itertools import ifilterfalse as filterfalse Python 3.x3.0.0 from itertools import filterfalse which works...

First, install Node.js for your platform. In this example we'll create an HTTP server listening on port 1337, which sends Hello, World! to the browser. Note that, instead of using port 1337, you can use any port number of your choice which is currently not in use by any other service. The http mod...

Exponentiation can be used by using the builtin pow-function or the ** operator: 2 ** 3 # 8 pow(2, 3) # 8 For most (all in Python 2.x) arithmetic operations the result's type will be that of the wider operand. This is not true for **; the following cases are exceptions from this rule: B...

The math-module contains another math.pow() function. The difference to the builtin pow()-function or ** operator is that the result is always a float: import math math.pow(2, 2) # 4.0 math.pow(-2., 2) # 4.0 Which excludes computations with complex inputs: math.pow(2, 2+0j) TypeErro...

Both the math and cmath-module contain the Euler number: e and using it with the builtin pow()-function or **-operator works mostly like math.exp(): import math math.e ** 2 # 7.3890560989306495 math.exp(2) # 7.38905609893065 import cmath cmath.e ** 2 # 7.3890560989306495 cmath.exp(2) # (...

The math module contains the expm1()-function that can compute the expression math.e ** x - 1 for very small x with higher precision than math.exp(x) or cmath.exp(x) would allow: import math print(math.e ** 1e-3 - 1) # 0.0010005001667083846 print(math.exp(1e-3) - 1) # 0.0010005001667083846 p...

Supposing you have a class that stores purely integer values: class Integer(object): def __init__(self, value): self.value = int(value) # Cast to an integer def __repr__(self): return '{cls}({val})'.format(cls=self.__class__.__name__, ...

Click the Run button in the toolbar (or press ⌘R) to build & run your project. Click Stop (or press ⌘.) to stop execution.   Click & hold to see the other actions, Test (⌘U), Profile (⌘I), and Analyze (⇧⌘B). Hold down modifier keys ⌥ option, ⇧ shift, and ⌃ control for more variants.  ...

A submodule references a specific commit in another repository. To check out the exact state that is referenced for all submodules, run git submodule update --recursive Sometimes instead of using the state that is referenced you want to update to your local checkout to the latest state of that s...

You can have multiple versions of Xcode installed at the same time (including beta versions). Simply rename the application in Finder to avoid conflicts. Note: Installing Xcode from the App Store will tend to overwrite an existing version on your machine. You can also install Xcode from a direct ...

list and tuple have an index-method to get the position of the element: alist = [10, 16, 26, 5, 2, 19, 105, 26] # search for 16 in the list alist.index(16) # 1 alist[1] # 16 alist.index(15) ValueError: 15 is not in list But only returns the position of the first found element: ...

Let's say we have a query of the remaining horsemen that needs to populate a Person class. NameBornResidenceDaniel Dennett1942United States of AmericaSam Harris1967United States of AmericaRichard Dawkins1941United Kingdom public class Person { public string Name { get; set; } public int...

Let's look at a more complex example that contains a one-to-many relationship. Our query will now contain multiple rows containing duplicate data and we will need to handle this. We do this with a lookup in a closure. The query changes slightly as do the example classes. IdNameBornCountryIdCountry...

Sometimes the number of types you are mapping exceeds the 7 provided by the Func<> that does the construction. Instead of using the Query<> with the generic type argument inputs, we will provide the types to map to as an array, followed by the mapping function. Other than the initial ma...