Tutorial by Examples: b

For more advanced regex operations it's best to use CL_ABAP_REGEX and its related classes. DATA: lv_test TYPE string, lo_regex TYPE REF TO cl_abap_regex. lv_test = 'The quick brown fox'. CREATE OBJECT lo_regex EXPORTING pattern = 'q(...)\w'. DATA(lo_matcher) = lo_regex->cr...

The first mistake that nearly every single programmer makes is presuming that this code will work as intended: float total = 0; for(float a = 0; a != 2; a += 0.01f) { total += a; } The novice programmer assumes that this will sum up every single number in the range 0, 0.01, 0.02, 0.03, .....

Groovy's safe navigation operator allows to avoid NullPointerExceptions when accessing to methods or attributes on variables that may assume null values. It is equivalent to nullable_var == null ? null : nullable_var.myMethod() def lst = ['foo', 'bar', 'baz'] def f_value = lst.find { it.startsWi...

for numbers, a zero value evaluates to false, non zero to true int i = 0 ... if (i) print "some ${i}" else print "nothing" will print "nothing"

a string (including GStrings) evaluates to true if not null and not empty, false if null or empty def s = '' ... if (s) println 's is not empty' else println 's is empty' will print: 's is empty'

Collections and Maps evaluates to true if not null and not empty and false if null or empty /* an empty map example*/ def userInfo = [:] if (!userInfo) userInfo << ['user': 'Groot', 'species' : 'unknown' ] will add user: 'Groot' , species : 'unknown' as default userInfo since the u...

a null object reference evaluates to false, a non null reference to true, but for for strings, collections, iterators and enumerations it also takes into account the size. def m = null if (!m) println "empty" else println "${m}" will print "empty" de...

Sometimes it may be useful to have a specific asBoolean definition in your own program for some kind of objects. /** an oversimplified robot controller */ class RunController { def complexCondition int position = 0 def asBoolean() { return complexCondition(this...

Not all type erasure involves virtual inheritance, allocations, placement new, or even function pointers. What makes type erasure type erasure is that it describes a (set of) behavior(s), and takes any type that supports that behavior and wraps it up. All information that isn't in that set of beha...

The population count of a bitstring is often needed in cryptography and other applications and the problem has been widely studied. The naive way requires one iteration per bit: unsigned value = 1234; unsigned bits = 0; // accumulates the total number of bits set in `n` for (bits = 0; value; ...

You can default to the normal Mongo format by defining your collections with the idGeneration field. MyCollection = new Meteor.Collection('mycollection', {idGeneration : 'MONGO'});

If the Node event loop acts like a bicycle chain, the server-side collection observer is like a derailleur. It's a gearing mechanism that is going to sit on the data collection as the data comes in. It can be very performant, as all race bicycles have derailleurs. But it's also a source for breaking...

Texttastic Code Editor - Code editor with syntax highlighting for iOS devices. Working Copy - Clone Github repositories to your iPad and code on the go. CodeHub - Browse and maintain your GitHub repositories. Management tool. iOctocat - Social utility for following Github projects. iMockups fo...

Inspecting an Object You can find the public methods an object can respond to using either the methods or public_methods methods, which return an array of symbols: class Foo def bar; 42; end end f = Foo.new def f.yay; 17; end p f.methods.sort #=> [:!, :!=, :!~, :<=>, :==, :===, :=...

It is possible to query an object about its instance variables using instance_variables, instance_variable_defined?, and instance_variable_get, and modify them using instance_variable_set and remove_instance_variable: class Foo attr_reader :bar def initialize @bar = 42 end end f = F...

The Kernel exposes methods for getting the list of global_variables and local_variables: cats = 42 $demo = "in progress" p global_variables.sort #=> [:$!, :$", :$$, :$&, :$', :$*, :$+, :$,, :$-0, :$-F, :$-I, :$-K, :$-W, :$-a, #=> :$-d, :$-i, :$-l, :$-p, :$-v, :$-w, :$...

Classes and modules have the same methods for introspecting instance variables as any other object. Class and modules also have similar methods for querying the class variables (@@these_things): p Module.methods.grep(/class_variable/) #=> [:class_variables, :class_variable_get, :remove_class_va...

It is a common practice to set application variables to an object scope. This keeps them easy to identify and distinguish from variables in other scopes. The Variables scope in a CFC is private to the CFC. When you set variables in this scope, they cannot be seen by pages that invoke the CFC. <...

pie view - (void)drawRect:(CGRect)rect { NSArray *data = @[@30, @15, @5, @17, @3, @10, @20]; // 1. context CGContextRef cxtRef = UIGraphicsGetCurrentContext(); CGPoint center = CGPointMake(150, 150); CGFloat radius = 150; __block CGFloat startAngle = 0; ...

Alert controller has a property which is used to put emphases on an action added in the alert controller. This property can be used to highlight a particular action for user attention.For objective C; @property(nonatomic, strong) UIAlertAction *preferredAction An action which is already added in...