Tutorial by Examples: a

Lists def lst = ['foo', 'bar', 'baz'] // using implicit argument lst.each { println it } // using explicit argument lst.each { val -> println val } // both print: // foo // bar // baz Iterate with index def lst = ['foo', 'bar', 'baz'] // explicit arguments are required lst.each...

def lst = ['foo', 'bar', 'baz'] lst.collect { it } // ['foo', 'bar', 'baz'] lst.collect { it.toUpperCase() } // ['FOO', 'BAR', 'BAZ'] To collect keys or values from a maps def map = [foo: 'FOO', bar: 'BAR', baz: 'BAZ'] def keys = map.collect { it.key } // ['foo', 'bar', 'baz'] def vals = m...

def lst = [10, 20, 30, 40] lst.findAll { it > 25 } // [30, 40]

def lst = [10, 20, 30, 40] lst.find { it > 25 } // 30. Note: it returns a single value

From lists def lst = ['foo', 'bar', 'baz'] // for each entry return a list containing [key, value] lst.collectEntries { [it, it.toUpperCase()] } // [foo: FOO, bar: BAR, baz: BAZ] // another option, return a map containing the single entry lst.collectEntries { [(it): it.toUpperCase()] } // [...

Apply the transformation to non-collection entries, delving into nested collections too and preserving the whole structure. def lst = ['foo', 'bar', ['inner_foo', 'inner_bar']] lst.collectNested { it.toUpperCase() } // [FOO, BAR, [INNER_FOO, INNER_BAR]]

def lst = ['foo', 'bar', ['inner_foo', 'inner_bar']] lst.flatten() ​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​...

def lst = ['foo', 'foo', 'bar', 'baz'] // *modifies* the list removing duplicate items lst.unique() // [foo, bar, baz] // setting to false the "mutate" argument returns a new list, leaving the original intact lst.unique(false) // [foo, bar, baz] // convert the list to a Set, thu...

# operator or stringizing operator is used to convert a Macro parameter to a string literal. It can only be used with the Macros having arguments. // preprocessor will convert the parameter x to the string literal x #define PRINT(x) printf(#x "\n") PRINT(This line will be converted to...

This is an example on how to use React Native's BackAndroid along with the Navigator. componentWillMount registers an event listener to handle the taps on the back button. It checks if there is another view in the history stack, and if there is one, it goes back -otherwise it keeps the default beha...

Here's a simple example that uses XSLT to convert data in an XML file into a table in an HTML file. You can use it to experiment with simple XSLT transforms. Prerequisite: Install a Java Runtime Environment and add the location of the JRE to your PATH variable. (On Windows, most installers will add...

class ImageExample extends Component { render() { return ( <View> <Image style={{width: 30, height: 30}} source={{uri: 'http://facebook.github.io/react/img/logo_og.png'}} /> </View> ); } }

You can start the remote debugging from Developer menu. After selecting the enable remote debugging it will open Google Chrome, So that you can log the output into your console. You can also write debugger syntax into your js code.

Prefix bitwise operators Bitwise operators are like logical operators but executed per bit rather than per boolean value. // bitwise NOT ~: sets all unset bits and unsets all set bits printf("%'06b", ~0b110110); // 001001 Bitmask-bitmask operators Bitwise AND &: a bit is set onl...

While catching the Throwable, Exception, Error and RuntimeException exceptions is bad, throwing them is even worse. The basic problem is that when your application needs to handle exceptions, the presence of the top level exceptions make it hard to discriminate between different error conditions. ...

Controls how the image should be resized or moved to match the size of ImageView. XML attribute: android:scaleType="..." i will illustrate different scale types with a square ImageView which has a black background and we want to display a rectangular drawable in white background in Im...

SELECT * INTO NewTable FROM OldTable Creates a new table with structure of old table and inserts all rows into the new table. Some Restrictions You cannot specify a table variable or table-valued parameter as the new table. You cannot use SELECT…INTO to create a partitioned table, even whe...

The following example can be used to find the total row count for a specific table in a database if table_name is replaced by the the table you wish to query: SELECT COUNT(*) AS [TotalRowCount] FROM table_name; It is also possible to get the row count for all tables by joining back to the table'...

This is something that can be frustrating: you make a visualisation using D3.js but the rectangle you want on top is hidden behind another rectangle, or the line you planned to be behind some circle is actually over it. You try to solve this using the z-index in your CSS, but it doesn't work (in SVG...

enum Fruit { apple, banana } main() { var a = Fruit.apple; switch (a) { case Fruit.apple: print('it is an apple'); break; } // get all the values of the enums for (List<Fruit> value in Fruit.values) { print(value); } // get the second val...