Tutorial by Examples: er

You can use the map operator to map the values of a stream to different values based on the outcome for each value from the function passed to map. The outcome stream is a new copy and will not modify the provided stream of values, the result stream will have the same length of the input stream but ...

This example finds an array of approximately evenly spaced points along a cubic Bezier curve. It decomposes Path segments created with context.bezierCurveTo into points along that curve. // Return: an array of approximately evenly spaced points along a cubic Bezier curve // // Attribution: Stack...

Formula in A1 ={"Item name","Quantity";"Apples",2;"Blueberries",5} Important: In certain countries the comma is used as a decimal separator (e.g: €1,00). If that's your case, you would need to use backslashes ( \ ) instead: (Docs) ={"Item name"\...

Interpolation means that Perl interpreter will substitute the values of variables for their name and some symbols (which are impossible or difficult to type in directly) for special sequences of characters (it is also known as escaping). The most important distinction is between single and double qu...

Perl interpolates variable names: my $name = 'Paul'; print "Hello, $name!\n"; # Hello, Paul! my @char = ('a', 'b', 'c'); print "$char[1]\n"; # b my %map = (a => 125, b => 1080, c => 11); print "$map{a}\n"; # 125 Arrays may be interpolated as a whol...

First, define a used defined table type to use: CREATE TYPE names as TABLE ( FirstName varchar(10), LastName varchar(10) ) GO Create the stored procedure: CREATE PROCEDURE prInsertNames ( @Names dbo.Names READONLY -- Note: You must specify the READONLY ) AS INSERT INTO d...

For expressing the power of 2 (2^n) of integers, one may use a bitshift operation that allows to explicitly specify the n. The syntax is basically: int pow2 = 1<<n; Examples: int twoExp4 = 1<<4; //2^4 int twoExp5 = 1<<5; //2^5 int twoExp6 = 1<<6; //2^6 ... int twoEx...

Assume you have a custom file you want to create an importer for. It could be an .xls file or whatever. In this case we're going to use a JSON file because it's easy but we're going to pick a custom extension to make it easy to tell which files are ours? Let's assume the format of the JSON file is ...

The "right-left" rule is a completely regular rule for deciphering C declarations. It can also be useful in creating them. Read the symbols as you encounter them in the declaration... * as "pointer to" - always on the left side [] as "array of" ...

In order to compile docker its recommended you have at least 2 GB RAM. Even with that it fails sometimes so its better to go for 4GB instead. make sure git and make is installed sudo apt-get install make git-core -y install a new kernel (at least 4.2) sudo apt-get install linux-generic...

# create docker container export cid=$(docker run -d --security-opt seccomp:unconfined busybox /bin/sh -c 'i=0; while true; do echo $i; i=$(expr $i + 1); sleep 1; done') # container is started and prints a number every second # display the output with docker logs $cid # checkpoint the cont...

SELECT * FROM Employee FOR SYSTEM_TIME BETWEEN '2014-01-01 00:00:00.0000000' AND '2015-01-01 00:00:00.0000000' WHERE EmployeeID = 1000 ORDER BY ValidFrom;

Required compiler features can be specified on a target using the command target_compile_features: add_library(foo foo.cpp ) target_compile_features(foo PRIVATE # scope of the feature cxx_constexpr # list of features ) The features must be part of CMAKE_C_COMPILE_FE...

You can iterate over the contents of a dictionary with dict for, which is similar to foreach: set theDict {abcd {ab cd} bcde {ef gh} cdef {ij kl}} dict for {theKey theValue} $theDict { puts "$theKey -> $theValue" } This produces this output: abcd -> ab cd bcde -> ef gh c...

Sometimes you need to match a literal (sub-)string with a regular expression despite that substring containing RE metacharacters. While yes, it's possible to write code to insert appropriate backslashes to make that work (using string map) it is easiest to just prefix the pattern with ***=, which ma...

DECLARE CURSOR c_emp_to_be_raised(p_sal emp.sal%TYPE) IS SELECT * FROM emp WHERE sal < p_sal; BEGIN FOR cRowEmp IN c_emp_to_be_raised(1000) LOOP dbms_Output.Put_Line(cRowEmp .eName ||' ' ||cRowEmp.sal||'... should be raised ;)'); END LOOP; END; /

A downcast can be used to make use of a subclass's code and data inside of a function taking a parameter of its superclass. class Rat { var color = "white" } class PetRat: Rat { var name = "Spot" } func nameOfRat(🐭: Rat) -> String { guard let petRat = ...

Converts the specified string representation of a date and time to its DateTime equivalent using the specified format and culture-specific format information. The format of the string representation must match the specified format exactly. Convert a specific format string to equivalent DateTime Le...

The loop macro supports iteration over the keys, the values, or the keys and values of a hash table. The following examples show possibilities, but the full loop syntax allows more combinations and variants. Over keys and values (let ((ht (make-hash-table))) (setf (gethash 'a ht) 1 (g...

The keys and values of a hash table can be iterated over using the macro with-hash-table-iterator. This may be a bit more complex than maphash or loop, but it could be used to implement the iteration constructs used in those methods. with-hash-table-iterator takes a name and a hash table and binds...