Tutorial by Examples: r

Installation or Setup

Google Apps Script does not require setup or installation. The only requirement is a Google Account. A Gmail account works as well as a Google Apps for Work/Education/Government account. You can create a new Google account by going to accounts.google.com Start your first script by going to script.g...

Declaring a property

At its simplest, a property is a function which returns a Bool. prop_reverseDoesNotChangeLength xs = length (reverse xs) == length xs A property declares a high-level invariant of a program. The QuickCheck test runner will evaluate the function with 100 random inputs and check that the result is...

Dynamic class creation

Classes can be created dynamically through the use of Class.new. # create a new class dynamically MyClass = Class.new # instantiate an object of type MyClass my_class = MyClass.new In the above example, a new class is created and assigned to the constant MyClass. This class can be instanti...

Joining Strings with a delimiter

Java SE 8 An array of strings can be joined using the static method String.join(): String[] elements = { "foo", "bar", "foobar" }; String singleString = String.join(" + ", elements); System.out.println(singleString); // Prints "foo + bar + foobar&qu...

Current Date and Time

R is able to access the current date, time and time zone: Sys.Date() # Returns date as a Date object ## [1] "2016-07-21" Sys.time() # Returns date & time at current locale as a POSIXct object ## [1] "2016-07-21 10:04:39 CDT" as.numeric(Sys...

Formatting Dates

To format Dates we use the format(date, format="%Y-%m-%d") function with either the POSIXct (given from as.POSIXct()) or POSIXlt (given from as.POSIXlt()) d = as.Date("2016-07-21") # Current Date Time Stamp format(d,"%a") # Abbreviated Weekday ## [1] &qu...

Formatting and printing date-time objects

# test date-time object options(digits.secs = 3) d = as.POSIXct("2016-08-30 14:18:30.58", tz = "UTC") format(d,"%S") # 00-61 Second as integer ## [1] "30" format(d,"%OS") # 00-60.99… Second as fractional ## [1] "30.579" for...

Parsing strings into date-time objects

The functions for parsing a string into POSIXct and POSIXlt take similar parameters and return a similar-looking result, but there are differences in how that date-time is stored; see "Remarks." as.POSIXct("11:38", # time string format = "...

Getting Started: Hello world!

Creating an HTML document and enabling knockout.js Create an HTML file and include knockout.js via a <script> tag. <!DOCTYPE html> <html> <head> <title>Hello world! (knockout.js)</title> </head> <body> <script src="https://cdnjs...

Checking a single property

The quickCheck function tests a property on 100 random inputs. ghci> quickCheck prop_reverseDoesNotChangeLength +++ OK, passed 100 tests. If a property fails for some input, quickCheck prints out a counterexample. prop_reverseIsAlwaysEmpty xs = reverse xs == [] -- plainly not true for all ...

First Module and Hello World

To start coding in the first place, you have to right click your VBA Project in the left list and add a new Module. Your first Hello-World Code could look like this: Sub HelloWorld() MsgBox "Hello, World!" End Sub To test it, hit the Play-Button in your Toolbar or simply hit the...

INSERT on specific columns

To do an insert on specific columns (as opposed to all of them) you must specify the columns you want to update. INSERT INTO USERS (FIRST_NAME, LAST_NAME) VALUES ('Stephen', 'Jiang'); This will only work if the columns that you did not list are nullable, identity, timestamp data type or compute...

INSERT multiple rows of data

To insert multiple rows of data in SQL Server 2008 or later: INSERT INTO USERS VALUES (2, 'Michael', 'Blythe'), (3, 'Linda', 'Mitchell'), (4, 'Jillian', 'Carson'), (5, 'Garrett', 'Vargas'); To insert multiple rows of data in earlier versions of SQL Server, use "UNION ALL" like so: ...

INSERT a single row of data

A single row of data can be inserted in two ways: INSERT INTO USERS(Id, FirstName, LastName) VALUES (1, 'Mike', 'Jones'); Or INSERT INTO USERS VALUES (1, 'Mike', 'Jones'); Note that the second insert statement only allows the values in exactly the same order as the table columns whereas in...

Copying contents from one slice to another slice

If you wish to copy the contents of a slice into an initially empty slice, following steps can be taken to accomplish it- Create the source slice: var sourceSlice []interface{} = []interface{}{"Hello",5.10,"World",true} Create the destination slice, with: Length =...
Go • Slices

The Pipe Operator

The Pipe Operator |> takes the result of an expression on the left and feeds it as the first parameter to a function on the right. expression |> function Use the Pipe Operator to chain expressions together and to visually document the flow of a series of functions. Consider the following:...

DECIMAL and NUMERIC

Fixed precision and scale decimal numbers. DECIMAL and NUMERIC are functionally equivalent. Syntax: DECIMAL ( precision [ , scale] ) NUMERIC ( precision [ , scale] ) Examples: SELECT CAST(123 AS DECIMAL(5,2)) --returns 123.00 SELECT CAST(12345.12 AS NUMERIC(10,5)) --returns 12345.12000

FLOAT and REAL

Approximate-number data types for use with floating point numeric data. SELECT CAST( PI() AS FLOAT) --returns 3.14159265358979 SELECT CAST( PI() AS REAL) --returns 3.141593

Integers

Exact-number data types that use integer data. Data typeRangeStoragebigint-2^63 (-9,223,372,036,854,775,808) to 2^63-1 (9,223,372,036,854,775,807)8 Bytesint-2^31 (-2,147,483,648) to 2^31-1 (2,147,483,647)4 Bytessmallint-2^15 (-32,768) to 2^15-1 (32,767)2 Bytestinyint0 to 2551 Byte

BINARY and VARBINARY

Binary data types of either fixed length or variable length. Syntax: BINARY [ ( n_bytes ) ] VARBINARY [ ( n_bytes | max ) ] n_bytes can be any number from 1 to 8000 bytes. max indicates that the maximum storage space is 2^31-1. Examples: SELECT CAST(12345 AS BINARY(10)) -- 0x0000000000000000...

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