Tutorial by Examples: ect

to check if the given path is a directory dirname = '/home/john/python' os.path.isdir(dirname) to check if the given path is a file filename = dirname + 'main.py' os.path.isfile(filename) to check if the given path is symbolic link symlink = dirname + 'some_sym_link' os.path.islink(symli...

One of the primary uses for this cv-qualifiers is const correctness. This is the practice of guaranteeing that only accesses that need to modify an object are able to modify the object, and that any (member or non-member) function that doesn't need to modify an object doesn't have write access to t...

Now that you're running Parse Server, it is time to save your first object. We'll use the REST API, but you can easily do the same using any of the Parse SDKs. Run the following: curl -X POST \ -H "X-Parse-Application-Id: APPLICATION_ID" \ -H "Content-Type: application/json" \...

The following example uses expect and receive to mock an Order's call to a CreditCardService, so that the test passes only if the call is made without having to actually make it. class Order def cancel CreditCardService.instance.refund transaction_id end end describe Order do des...

Some programmers think that it is a good idea to save space by using a null to represent an empty array or collection. While it is true that you can save a small amount of space, the flipside is that it makes your code more complicated, and more fragile. Compare these two versions of a method for ...

On StackOverflow, we often see code like this in Answers: public String joinStrings(String a, String b) { if (a == null) { a = ""; } if (b == null) { b = ""; } return a + ": " + b; } Often, this is accompanied with an asse...

Starting with a binary image, bwImg, which contains a number of connected objects. >> bwImg = imread('blobs.png'); >> figure, imshow(bwImg), title('Binary Image') To measure properties (e.g., area, centroid, etc) of every object in the image, use regionprops: >> stats = reg...

By default, Import-CSV imports all values as strings, so to get DateTime- and integer-objects, we need to cast or parse them. Using Foreach-Object: > $listOfRows = Import-Csv .\example.csv > $listOfRows | ForEach-Object { #Cast properties $_.DateTime = [datetime]$_.DateTime $...

from paramiko import client ssh = client.SSHClient() # create a new SSHClient object ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy()) #auto-accept unknown host keys ssh.connect(hostname, username=username, port=port, password=password) #connect with a host stdin, stdout, stderr = ssh.ex...

This is a screenshot of a video playing. You see a normal 16:9 video like you would expect to see in any modern video solution. This - the aspect ratio that the viewer sees - is what is called the display aspect ratio or DAR. From the illustrated parameters, we see that DAR = 1280:720 = 16:9 = 1....

Internally, all videos are a just series of pictures. Let's take a look at one such picture. That looks odd, right? Indeed. The pictures that make up a video may have an aspect ratio that are different from the DAR, most often for algorithmic reasons (e.g. only sizes that are a multiple of 16 can...

As the picture aspect ratio example indicates, videos are series of pictures that do not necessarily have the same aspect ratio as the final result to be displayed to the user. So how do you get from those stretched pictures to the normally displayed output? You need a stretching factor! This stret...

This is another name for sample aspect ratio and should be avoided, as the natural acronym (PAR) conflicts with picture aspect ratio.

Using a list object you can create a fully functional generic Stack with helper methods such as peeking and checking if the stack is Empty. Check out the official python docs for using list as Stack here. #define a stack class class Stack: def __init__(self): self.items = [] ...

When you really need to script ssh connection, piping the password into the ssh command does not work (echo passw0rd | ssh host). It is because the password is not read from standard input, but directly from TTY (teleprinter, teletypewriter, Teletype for historical reasons). But there is sshpass to...

If there is no need for frontend in your next project, you can run sails new with additional flag --no-frontend. sails new NameOfProject --no-frontend This will generate everything needed for backend and will omit view, assets and grunt files. More about command line and sails-new: http://sails...

@Entity @Table(name="FOO") public class Foo { private UUID fooId; @OneToMany(mappedBy = "bar") private List<FooBar> bars; } @Entity @Table(name="BAR") public class Bar { private UUID barId; @OneToMany(mappedBy = "f...

@Entity @Table(name="FOO") public class Foo { private UUID fooId; @OneToMany @JoinTable(name="FOO_BAR", joinColumns = @JoinColumn(name="fooId"), inverseJoinColumns = @JoinColumn(name="barId")) private List<Bar&g...

@Entity @Table(name="FOO") public class Foo { private UUID fooId; @OneToMany(mappedBy = "bar") private List<Bar> bars; } @Entity @Table(name="BAR") public class Bar { private UUID barId; @ManyToOne @JoinColumn(nam...

@Entity @Table(name="FOO") public class Foo { private UUID fooId; @OneToOne(cascade = CascadeType.ALL) @JoinColumn(name = "barId") private Bar bar; } @Entity @Table(name="BAR") public class Bar { private UUID barId; ...