Tutorial by Examples: g

Unity works with hierarchies in order to keep your project organized. You can assign objects a place in the hierarchy using the editor but you can also do this through code. Parenting You can set an object's parent with the following methods var other = GetOtherGameObject(); other.transform.Se...

Sometimes you want to destructure key under a map which might not be present in the map, but you want a default value for the destructured value. You can do that this way: (def my-map {:a 3 :b 4}) (let [{a :a b :b :keys [c d] :or {a 1 c 2}} my-map] (println ...

Destructurling works in many places, as well as in the param list of an fn: (defn my-func [[_ a b]] (+ a b)) (my-func [1 2 3]) ;= 5 (my-func (range 5)) ;= 3 Destructuring also works for the & rest construct in the param list: (defn my-func2 [& [_ a b]] (+ a b)) (my-func2 1 ...

Destructuring also gives you the ability to interpret a sequence as a map: (def my-vec [:a 1 :b 2]) (def my-lst '("smthg else" :c 3 :d 4)) (let [[& {:keys [a b]}] my-vec [s & {:keys [c d]} my-lst] (+ a b c d)) ;= 10 It is useful for defining functions with named p...

Predicates that reason about instantiations are called meta-logical. Examples are: var/1 ground/1 integer/1 These predicates are outside the realm of pure monotonic logic programs, because they break properties like commutativity of conjunction. Other predicates that are meta-logical includ...

Our example array: arr=(a b c d e f) Using a for..in loop: for i in "${arr[@]}"; do echo "$i" done 2.04 Using C-style for loop: for ((i=0;i<${#arr[@]};i++)); do echo "${arr[$i]}" done Using while loop: i=0 while [ $i -lt ${#arr[@]} ]; do...

The MEDIAN function since Oracle 10g is an easy to use aggregation function: SELECT MEDIAN(SAL) FROM EMP It returns the median of the values Works on DATETIME values too. The result of MEDIAN is computed by first ordering the rows. Using N as the number of rows in the group, Oracle calcula...

Following code will release the lock. There will be no problem. Behind the scenes lock statement works as try finally lock(locker) { throw new Exception(); } More can be seen in the C# 5.0 Specification: A lock statement of the form lock (x) ... where x is an expression of a referenc...

The function toupper will convert a string to upper case (capital letters). For example: BEGIN { greeting = "hello" loud_greeting = toupper(greeting) print loud_greeting } This code will output "HELLO" when run.

We create a new concurrent process by calling the spawn function. The spawn function will get as parameter a function Fun that the process will evaluate. The return value of the spawn function is the created process identifier (pid). 1> Fun = fun() -> 2+2 end. #Fun<erl_eval.20.52032458&gt...

The routing configuration is included in your app/config/config.yml file, by default the app/config/routing.yml file. From there you can link to your own routing configuration in a bundle # app/config/routing.yml app: resource: "@AppBundle/Resources/config/routing.yml" It migh...

The routing configuration is included in your app/config/config.yml file, by default the app/config/routing.yml file. From there you can link to the controllers that have annotated routing configuration: # app/config/routing.yml app: resource: "@AppBundle/Controller" type: ...

A browser's debugging console can be used in order to print simple messages. This debugging or web console can be directly opened in the browser (F12 key in most browsers – see Remarks below for further information) and the log method of the console Javascript object can be invoked by typing the fol...

Sometimes, we may open a file which we do not have permission to write in Vim without using sudo. Use this command to save a read-only file edited in Vim. :w !sudo tee > /dev/null % Which you could map to :w!! in your .vimrc: cmap w!! w !sudo tee > /dev/null % You will be presented a ...

Starter code to create and remove a full page canvas that responds to resize events via javascript. var canvas; // Global canvas reference var ctx; // Global 2D context reference // Creates a canvas function createCanvas () { const canvas = document.createElement(&q...

There are many situation where you want to draw an image that is rotated, scaled, and translated. The rotation should occur around the center of the image. This is the quickest way to do so on the 2D canvas. These functions a well suited to 2D games where the expectation is to render a few hundred e...

In the simplest use-case, just navigate to the directory your file is in, and type: pyinstaller myfile.py Pyinstaller analyzes the file and creates: A myfile.spec file in the same directory as myfile.py A build folder in the same directory as myfile.py A dist folder in the same directory as m...

pg_dump -Fc -f DATABASE.pgsql DATABASE The -Fc selects the "custom backup format" which gives you more power than raw SQL; see pg_restore for more details. If you want a vanilla SQL file, you can do this instead: pg_dump -f DATABASE.sql DATABASE or even pg_dump DATABASE > DATABA...

psql < backup.sql A safer alternative uses -1 to wrap the restore in a transaction. The -f specifies the filename rather than using shell redirection. psql -1f backup.sql Custom format files must be restored using pg_restore with the -d option to specify the database: pg_restore -d DATABA...

$ pg_dumpall -f backup.sql This works behind the scenes by making multiple connections to the server once for each database and executing pg_dump on it. Sometimes, you might be tempted to set this up as a cron job, so you want to see the date the backup was taken as part of the filename: $ post...