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Constants are declared like variables, but using the const keyword: const Greeting string = "Hello World" const Years int = 10 const Truth bool = true Like for variables, names starting with an upper case letter are exported (public), names starting with lower case are not. // not e...

Change Index Initialize or update a particular element in the array array[10]="elevenths element" # because it's starting with 0 3.1 Append Modify array, adding elements to the end if no subscript is specified. array+=('fourth element' 'fifth element') Replace the entire ar...

Sqoop ships as one binary package however it’s compound from two separate parts client and server. You need to install server on single node in your cluster. This node will then serve as an entry point for all connecting Sqoop clients. Server acts as a mapreduce client and therefore Hadoop must b...

This is the primary purpose of cat. cat file1 file2 file3 > file_all cat can also be used similarly to concatenate files as part of a pipeline, e.g. cat file1 file2 file3 | grep foo

To get a verbose list of all devices connected to adb, write the following command in your terminal: adb devices -l Example Output List of devices attached ZX1G425DC6 device usb:336592896X product:shamu model:Nexus_6 device:shamu 013e4e127e59a868 device usb:337641472X produc...

Write the following command in your terminal: adb shell getprop This will print all available information in the form of key/value pairs. You can just read specific information by appending the name of a specific key to the command. For example: adb shell getprop ro.product.model Here are a...

The example shows parsing a JSON object using the Gson library from Google. Parsing objects: class Robot { //OPTIONAL - this annotation allows for the key to be different from the field name, and can be omitted if key and field name are same . Also this is good coding practice as it decouple ...

Prerequisites To run the Play framework, you need Java 6 or later. If you wish to build Play from source, you will need the Git source control client to fetch the source code and Ant to build it. Be sure to have Java in the current path (enter java --version to check) Play will use the default Ja...

An alternative community de facto standard is an addon called ember-concurrency that makes a lot of the promise confusion go away. It can be installed with the command ember install ember-concurrency. Pros Intuitive reasoning of complex asynchronous code. Offers a complete API for managing tas...

After creating a new model or modifying existing models, you will need to generate migrations for your changes and then apply the migrations to the specified database. This can be done by using the Django's built-in migrations system. Using the manage.py utility when in the project root directory: ...

Units of measure are additional type annotations that can be added to floats or integers. They can be used to verify at compile time that calculations are using units consistently. To define annotations: [<Measure>] type m // meters [<Measure>] type s // seconds [<Measure>] typ...

You can use traits to modify methods of a class, using traits in stackable fashion. The following example shows how traits can be stacked. The ordering of the traits are important. Using different order of traits, different behavior is achieved. class Ball { def roll(ball : String) = println(&q...

Detailed instructions on getting asp.net-web-api set up or installed.

All looping constructs allow the use of break and continue statements. They affect the immediately surrounding (innermost) loop. Basic Loop Control break terminates the loop: for x in 0..5 { if x > 2 { break; } println!("{}", x); } Output 0 1 2 continue finishes...

While many people think that ^ means the start of a string, it actually means start of a line. For an actual start of string anchor use, \A. The string hello\nworld (or more clearly) hello world Would be matched by the regular expressions ^h, ^w and \Ah but not by \Aw

With IronPython you can access any .net assembly which is compiled using the same or a lower version than the IronPython core. Example: Importing a a .net assembly and class from System import Math Example: Using an imported class: from System import Math print Math.Abs(-123) You can also lo...

To find out the IP address of your container, use: docker inspect <container id> | grep IPAddress or use docker inspect docker inspect --format '{{ .NetworkSettings.IPAddress }}' ${CID}

Payments Table CustomerPayment_typeAmountPeterCredit100PeterCredit300JohnCredit1000JohnDebit500 select customer, sum(case when payment_type = 'credit' then amount else 0 end) as credit, sum(case when payment_type = 'debit' then amount else 0 end) as debit from payments group by ...

Maps in go are not safe for concurrency. You must take a lock to read and write on them if you will be accessing them concurrently. Usually the best option is to use sync.RWMutex because you can have read and write locks. However, a sync.Mutex could also be used. type RWMap struct { sync.RWMut...

Doctrine 2 is easy to install via composer composer require doctrine/orm but it can also be downloaded from http://www.doctrine-project.org/projects/orm.html or from its GitHub project page.