Tutorial by Examples: re

ggplot2 works best with a long data frame. The following sample data which represents the prices for sweets on 20 different days, in a format described as wide, because each category has a column. set.seed(47) sweetsWide <- data.frame(date = 1:20, chocolate = run...

Java doesn't provide a direct method in java.util.Arrays to remove an element from an array. To perform it, you can either copy the original array to a new one without the element to remove or convert your array to another structure allowing the removal. Using ArrayList You can convert the array t...

Java provides specialized Streams for three types of primitives IntStream (for ints), LongStream (for longs) and DoubleStream (for doubles). Besides being optimized implementations for their respective primitives, they also provide several specific terminal methods, typically for mathematical operat...

private static final Interceptor REWRITE_CACHE_CONTROL_INTERCEPTOR = new Interceptor() { @Override public Response intercept(Interceptor.Chain chain) throws IOException { Response originalResponse = chain.proceed(chain.request()); return originalResponse.newBuilder() .header(&q...

To perform actions in Django using commandline or other services (where the user/request is not used), you can use the management commands. Django modules can be imported as needed. For each command a separate file needs to be created: myapp/management/commands/my_command.py (The management and...

This is an basic example on how to wire up and make an LED turn on/off when the pushbutton is pressed. /* Basic Digital Read * ------------------ * * turns on and off a light emitting diode(LED) connected to digital * pin 13, when pressing a pushbutton attached to pin 7. It illustrates...

If you want to calculate with BigDecimal you have to use the returned value because BigDecimal objects are immutable: BigDecimal a = new BigDecimal("42.23"); BigDecimal b = new BigDecimal("10.001"); a.add(b); // a will still be 42.23 BigDecimal c = a.add(b); // c will be ...

Module Pattern The Module pattern is a creational and structural design pattern which provides a way of encapsulating private members while producing a public API. This is accomplished by creating an IIFE which allows us to define variables only available in its scope (through closure) while return...

Under the hood, a matrix is a special kind of vector with two dimensions. Like a vector, a matrix can only have one data class. You can create matrices using the matrix function as shown below. matrix(data = 1:6, nrow = 2, ncol = 3) ## [,1] [,2] [,3] ## [1,] 1 3 5 ## [2,] 2 4...

You can specify different application IDs or package names for each buildType or productFlavor using the applicationIdSuffix configuration attribute: Example of suffixing the applicationId for each buildType: defaultConfig { applicationId "com.package.android" minSdkVersion 17 ...

A compound view is a custom ViewGroup that's treated as a single view by the surrounding program code. Such a ViewGroup can be really useful in DDD-like design, because it can correspond to an aggregate, in this example, a Contact. It can be reused everywhere that contact is displayed. This means t...

This example listens for input coming in over the serial connection, then repeats it back out the same connection. byte incomingBytes; void setup() { Serial.begin(9600); // Opens serial port, sets data rate to 9600 bps. } void loop() { // Send data only when you receive...

Sometimes, we need to update the progress of the computation done by an AsyncTask. This progress could be represented by a string, an integer, etc. To do this, we have to use two functions. First, we need to set the onProgressUpdate function whose parameter type is the same as the second type parame...

Let's say we have the following structure: struct MY_STRUCT { int my_int; float my_float; }; We can define MY_STRUCT to omit the struct keyword so we don't have to type struct MY_STRUCT each time we use it. This, however, is optional. typedef struct MY_STRUCT MY_STRUCT; If we th...

When filtering an email address filter_var() will return the filtered data, in this case the email address, or false if a valid email address cannot be found: var_dump(filter_var('[email protected]', FILTER_VALIDATE_EMAIL)); var_dump(filter_var('notValidEmail', FILTER_VALIDATE_EMAIL)); Results: ...

const auto input = "Some people, when confronted with a problem, think \"I know, I'll use regular expressions.\""s; smatch sm; cout << input << endl; // If input ends in a quotation that contains a word that begins with "reg" and another word begining...

This code takes in various brace styles and converts them to One True Brace Style: const auto input = "if (KnR)\n\tfoo();\nif (spaces) {\n foo();\n}\nif (allman)\n{\n\tfoo();\n}\nif (horstmann)\n{\tfoo();\n}\nif (pico)\n{\tfoo(); }\nif (whitesmiths)\n\t{\n\tfoo();\n\t}\n"s; cout &lt...

A std::regex_token_iterator provides a tremendous tool for extracting elements of a Comma Separated Value file. Aside from the advantages of iteration, this iterator is also able to capture escaped commas where other methods struggle: const auto input = "please split,this,csv, ,line,\\,\n&quot...

When processing of captures has to be done iteratively a regex_iterator is a good choice. Dereferencing a regex_iterator returns a match_result. This is great for conditional captures or captures which have interdependence. Let's say that we want to tokenize some C++ code. Given: enum TOKENS { ...

db.people.insert({name: 'Tom', age: 28}); Or db.people.save({name: 'Tom', age: 28}); The difference with save is that if the passed document contains an _id field, if a document already exists with that _id it will be updated instead of being added as new. Two new methods to insert documents...