Tutorial by Examples: u

Support vector machines is a family of algorithms attempting to pass a (possibly high-dimension) hyperplane between two labelled sets of points, such that the distance of the points from the plane is optimal in some sense. SVMs can be used for classification or regression (corresponding to sklearn.s...

One of the uses of recursion is to navigate through a hierarchical data structure, like a file system directory tree, without knowing how many levels the tree has or the number of objects on each level. In this example, you will see how to use recursion on a directory tree to find all sub-directorie...

It is a good idea to maintain a web-scraping session to persist the cookies and other parameters. Additionally, it can result into a performance improvement because requests.Session reuses the underlying TCP connection to a host: import requests with requests.Session() as session: # all req...

Because LINQ uses deferred execution, we can have a query object that doesn't actually contain the values, but will return the values when evaluated. We can thus dynamically build the query based on our control flow, and evaluate it once we are finished: IEnumerable<VehicleModel> BuildQuery(i...

First need to create a final static logger object: final static Logger logger = Logger.getLogger(classname.class); Then, call logging methods: //logs an error message logger.info("Information about some param: " + parameter); // Note that this line could throw a NullPointerException!...

Log4j gives you posibility to log data into console and file at same time. Create a log4j.properties file and put inside this basic configuration: # Root logger option log4j.rootLogger=DEBUG, stdout, file # Redirect log messages to console log4j.appender.stdout=org.apache.log4j.ConsoleAppende...

You can set an environment variable called PYTHONSTARTUP for Python's console. Whenever you enter the Python console, this file will be executed, allowing for you to add extra functionality to the console such as importing commonly-used modules automatically. If the PYTHONSTARTUP variable was set t...

Python has a variety of command-line switches which can be passed to py. These can be found by performing py --help, which gives this output on Python 3.4: Python Launcher usage: py [ launcher-arguments ] [ python-arguments ] script [ script-arguments ] Launcher arguments: -2 : Launch ...

The Python console adds a new function, help, which can be used to get information about a function or object. For a function, help prints its signature (arguments) and its docstring, if the function has one. >>> help(print) Help on built-in function print in module builtins: print(.....

A simple static file server would look like this: package main import ( "net/http" ) func main() { muxer := http.NewServeMux() fileServerCss := http.FileServer(http.Dir("src/css")) fileServerJs := http.FileServer(http.Dir("src/js")) file...

Install the SDK Download & unzip the SDK Make sure you are using the latest version of Xcode (7.0+) and targeting iOS 7.0 or highe Download SDK Add the SDKs to your app Drag the Parse.framework and Bolts.framework you downloaded into your Xcode project folder target. Make sure th...

Sometimes you need to keep a linear (non-branching) history of your code commits. If you are working on a branch for a while, this can be tricky if you have to do a regular git pull since that will record a merge with upstream. [alias] up = pull --rebase This will update with your upstream so...

You can use the star * when writing a function to collect all positional (ie. unnamed) arguments in a tuple: def print_args(farg, *args): print("formal arg: %s" % farg) for arg in args: print("another positional arg: %s" % arg) Calling method: print_args(1, &...

You can define a function that takes an arbitrary number of keyword (named) arguments by using the double star ** before a parameter name: def print_kwargs(**kwargs): print(kwargs) When calling the method, Python will construct a dictionary of all keyword arguments and make it available in ...

A common use case for *args in a function definition is to delegate processing to either a wrapped or inherited function. A typical example might be in a class's __init__ method class A(object): def __init__(self, b, c): self.y = b self.z = c class B(A): def __init__(...

You can use a dictionary to assign values to the function's parameters; using parameters name as keys in the dictionary and the value of these arguments bound to each key: def test_func(arg1, arg2, arg3): # Usual function with three arguments print("arg1: %s" % arg1) print("a...

Detailed instructions on getting facebook set up or installed.

NSLog(@"%s %@",__FUNCTION__, @"etc etc"); Inserts the class and method name into the output: 2016-07-22 12:51:30.099 loggingExample[18132:2971471] -[ViewController viewDidLoad] etc etc

You have a local vagrant box that you want to upload to Amazon AWS. First, you need to create a .box file: vagrant package --base my-virtual-machine This step should take a while depending on the size of your image. Then, you need to get the .vmdk image from the .box file: gunzip -S .box packag...

Introduce environment variable VAGRANT_DEFAULT_PROVIDER export VAGRANT_DEFAULT_PROVIDER=vmware_fusion