Augmented Assignment Python String
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Introduction to Groovy and Grails
Introduction to Groovy and Grails Mohamed Seifeddine November 25, 2009 1 Contents 1 Foreword 5 2 Introduction to Groovy 7 3 Getting started 9 3.1 Installing Groovy . .9 3.1.1 JDK - A Prerequisite . .9 3.1.2 Installing Groovy . .9 3.2 Updating Groovy . 10 3.3 Editors for Groovy and Grails . 10 3.4 groovysh, groovyConsole & groovy . 10 4 Boolean Evaluation, Elvis Operator & the Safe Navigation Op- erator 13 4.1 Elvis Operator . 15 4.2 Safe Navigation Operator . 15 5 String & GString 19 6 Classes, Dynamic type, Methods, Closures the & Meta-Object Protocol 21 6.1 Dynamic type . 25 6.2 Closure . 29 6.2.1 Create . 29 6.2.2 Call . 30 6.2.3 Getting Information . 33 6.2.4 Method Reference Pointer . 33 6.3 More on Methods . 35 6.3.1 Optional Parantheses . 35 6.3.2 Positional Parameters . 35 6.3.3 Optional Parameters . 36 6.3.4 Mapped Parameters . 37 6.3.5 Dynamic Method Call . 37 6.4 Meta-Object Protocol . 39 6.4.1 Adding Methods & Properties . 39 6.4.2 Add Constructor . 41 6.4.3 Intercepting Method Calls . 41 6.4.4 Getting Information . 42 7 Collections (List, Range, Map) and Iterative Object Methods 47 7.1 List . 47 7.2 Range . 50 7.3 Map . 52 8 Other 55 8.1 Groovy Switch . 55 8.2 Groovy SQL . 56 8.3 File . 58 8.4 Exception Handling . 60 2 8.5 Other . 60 9 Introduction to Grails 61 10 Getting Started 63 10.1 Installing Grails . -
Chapter 2 Core Basics
Chapter 2 Core Basics In this chapter we introduce some of the basic concepts that are important for understanding what is to follow. We also introduce a few of the fundamental operations that are involved in the vast majority of useful programs. 2.1 Literals and Types Section 1.3 introduced the string literal. A string literal is a collection of characters enclosed in quotes. In general, a literal is code that exactly represents a value. In addition to a string literal, there are numeric literals. There are actually a few different types of numeric values in Python. There are integer values which correspond to whole numbers (i.e., the countable numbers that lack a fractional part). In Python, an integer is known as an int. A number that can have a fractional part is called a float (a float corresponds to a real number). For example, 42 is an int while 3.14 is a float. The presence of the decimal point makes a number a float—it doesn’t matter if the fractional part is zero. For example, the literal 3.0, or even just 3., are also floats1 despite the fact that these numbers have fractional parts of zero.2 There are some important differences between how computers work with ints and floats. For example, ints are stored exactly in the computer while, in general, floats are only stored approximately. This is a consequence of the fact that we are entering numbers as decimal numbers, i.e., numbers in the base 10 counting system, but the computer stores these numbers internally as a finite number of binary (base 2) digits. -
Lecture 3: Its Time to See the C
Computer Science 61C Spring 2017 Friedland and Weaver Lecture 3: Its time to see the C... 1 Agenda Computer Science 61C Spring 2017 Friedland and Weaver • Computer Organization • Compile vs. Interpret • C vs Java 2 ENIAC (U.Penn., 1946) First Electronic General-Purpose Computer Computer Science 61C Spring 2017 Friedland and Weaver • Blazingly fast (multiply in 2.8ms!) • 10 decimal digits x 10 decimal digits • But needed 2-3 days to setup new program, as programmed with patch cords and switches • At that time & before, "computer" mostly referred to people who did calculations 3 EDSAC (Cambridge, 1949) First General Stored-Program Computer Computer Science 61C Spring 2017 Friedland and Weaver • Programs held as numbers in memory • This is the revolution: It isn't just programmable, but the program is just the same type of data that the computer computes on • 35-bit binary 2’s complement words 4 Components of a Computer Computer Science 61C Spring 2017 Friedland and Weaver Memory Processor Input Enable? Read/Write Control Program Datapath Address PC Bytes Write Registers Data Arithmetic & Logic Unit Read Data Output (ALU) Data Processor-Memory Interface I/O-Memory Interfaces 5 Great Idea: Levels of Representation/Interpretation Computer Science 61C Spring 2017 Friedland and Weaver temp = v[k]; High Level Language v[k] = v[k+1]; We are here! Program (e.g., C) v[k+1] = temp; lw $t0, 0($2) Compiler Anything can be represented lw $t1, 4($2) Assembly Language as a number, sw $t1, 0($2) Program (e.g., MIPS) i.e., data or instructions sw $t0, 4($2) -
Perception and Effects of Implementing Kotlin in Existing Projects
Bachelor thesis Undergraduate level Perception and effects of implementing Kotlin in existing projects A case study about language adoption Author: Emil Sundin Supervisor: Wei Song Examiner: Azadeh Sarkheyli Discipline: Informatics Course: IK2017 Credit: 15 credits Examination date: 2018-05-25 Dalarna University provides the opportunity for publishing the thesis through DiVA as Open Access. This means that the thesis work will become freely available to read and download through their portal. Dalarna University encourages students as well as researchers to publish their work in the Open Access format. We approve the publishing of this thesis work under the Open Access format: Yes ☒ No ☐ Dalarna University – SE-791 88 Falun – Phone +4623-77 80 00 Abstract The Kotlin programming language has seen an increase of adoption since its launch in 2011. In late 2017 Google announced first-class support for Kotlin on the Android platform which further popularized the language. With this increase in popularity we felt it was interesting to investigate how Kotlin affects the developer experience. We performed a case study to see how Java developers perceive the Kotlin language, and how it meets the requirements of these developers. To gather the developer requirements and their perception of Kotlin we performed two sets of interviews and rewrote parts of their codebase. The first set of interviews identified developer requirements and the second set of interviews showcased the Kotlin language and its potential use in their codebase. The results show that Kotlin can meet most of the developer requirements and that the perception of Kotlin is positive. Kotlin’s ability to be incrementally adopted was a prominent feature which reduced the inherent risks of technology adoption while providing them the ability to further evaluate the language. -
Unary Operator
Introduction to Python Operations and Variables 1 Topics 1) Arithmetic Operations 2) Floor Division vs True Division 3) Modulo Operator 4) Operator Precedence 5) String Concatenation 6) Augmented Assignment 2 Arithmetic Operations 3 Mixing Types Any expression that two floats produce a float. x = 17.0 – 10.0 print(x) # 7.0 When an expression’s operands are an int and a float, Python automatically converts the int to a float. x = 17.0 – 10 print(x) # 7.0 y = 17 – 10.0 print(y) # 7.0 4 True Division vs Floor Division The operator / is true division and the operator // returns floor division(round down after true divide). True divide / always gives the answer as a float. print(23 // 7) # 3 print(3 // 9) # 0 print(-4 // 3) # -2 print(6 / 5) # 1.2 print(6 / 3) # 2.0 NOT 2! 5 Remainder with % The % operator computes the remainder after floor division. • 14 % 4 is 2 • 218 % 5 is 3 3 43 4 ) 14 5 ) 218 12 20 2 18 15 3 Applications of % operator: • Obtain last digit of a number: 230857 % 10 is 7 • Obtain last 4 digits: 658236489 % 10000 is 6489 • See whether a number is odd: 7 % 2 is 1, 42 % 2 is 0 6 Modulo Operator The operator % returns the modulus which is the remainder after floor division. print(18 % 5) # 3 print(2 % 9) # 2, if first number is smaller, it's the answer print(125 % 10) # 5 print(0 % 10) # 0 print(10 % 0) # ZeroDivisionError 7 Why floor/modulo division is useful Floor division allows us to extract the integer part of the division while the modulo operator extracts the remainder part of the division. -
Icon Analyst 8
In-Depth Coverage of the Icon Programming Language October 1991 Number 8 subject := OuterEnvir.subject object := OuterEnvir.object s_pos := OuterEnvir.s_pos In this issue … o_pos := OuterEnvir.o_pos fail String Synthesis … 1 An Imaginary Icon Computer … 2 end Augmented Assignment Operations … 7 procedure Eform(OuterEnvir, e2) The Icon Compiler … 8 local InnerEnvir Programming Tips … 12 InnerEnvir := What’s Coming Up … 12 XformEnvir(subject, s_pos, object, o_pos) subject := OuterEnvir.subject String Synthesis object := OuterEnvir.object s_pos := OuterEnvir.s_pos In the last issue of the Analyst, we posed the problem o_pos := OuterEnvir.o_pos of implementing a string-synthesis facility for Icon, using the ideas given earlier about modeling the string-scanning control suspend InnerEnvir.object structure. OuterEnvir.subject := subject Our solution is given below. First we need procedures OuterEnvir.object := object analogous to the procedure used for modeling string scanning. OuterEnvir.s_pos := s_pos In addition to a subject, there’s now an “object”, which is the OuterEnvir.o_pos := o_pos result of string synthesis. There now also are two positions, subject := InnerEnvir.subject one in the subject and one in the object. The global identifiers object := InnerEnvir.object subject, object, s_pos, and o_pos are used for these four s_pos := InnerEnvir.s_pos “state variables” in the procedures that follow. (In a real o_pos := InnerEnvir.o_pos implementation, these would be keywords.) fail The string synthesis control structure is modeled as end expr1 ? expr2 → Eform(Bform(expr1),expr2) Most of the procedures specified in the last issue of the are straightforward. Care must be taken, however, The procedures Bform() and Eform() are very similar Analyst to assure that values assigned to the positions are in range — to Bscan() and Escan() used in the last issue of the Analyst this is done automatically for the keyword &pos, but it must for modeling string scanning. -
Groovy and Java: a Comparison Groovy’S Resemblance to Java Is Often Quite Striking
APPENDIX ■ ■ ■ The Groovy Language Groovy is an all-purpose programming language for the JVM. It was born in 2003 when James Strachan and Bob McWhirter founded the Groovy project with the goal of creating a glue lan- guage to easily combine existing frameworks and components. Groovy is a language that aims to bring the expressiveness of languages such as Ruby, Lisp, and Python to the Java platform while still remaining Java friendly. It attracted much excitement with these ambitious goals, because the majority of other scripting languages on the Java platform either used an entirely alien syntax and APIs or were simply Java without the need to specify types. Despite its youth, Groovy is a stable, feature-rich language that forms the perfect base for Grails. This is a fantastic achievement, given the limited resources available to an open source project such as Groovy. Groovy was an obvious choice as a platform for the Grails framework, because it provides the necessary underlying infrastructure to create the diverse range of miniature domain-specific languages utilized throughout Grails. ■Note Martin Fowler has written an excellent article about domain-specific languages: http://www.mar- tinfowler.com/bliki/DomainSpecificLanguage.html. What does this mean? Well, the syntax you see used throughout the book has often been magically enhanced and shortened by using a combination of Groovy’s already concise syntax and its support for metaprogramming. Groovy performs a lot of magic under the covers, abstracted away from the developer. This removes the burden from the programmer who would otherwise be required to write reams of unnecessary, repetitive code. -
View the Index
INDEX Numbers and Symbols __(double underscore), using in 256 objects and 257 objects, 154–155 dunder methods, 322. See also ./, using with Ubuntu, 42 underscore (_) /? command line argument, 25–26 / (forward slash) = assignment operator, 113 purpose of, 18 == comparison operator, 113, 336 using with command line chaining, 103, 105 arguments, 25 using to compare objects, 154 # (hash mark) using with None, 94–95 using with comments, 183 != comparison operator, 336 using with docstrings, 188 * and ** syntax [] (index operator), using, 117 using to create variadic functions, ; (semicolons), using with timeit 167–171 module, 226–227 using to create wrapper functions, ' (single quote), using, 46 171–172 ~ (tilde), using in macOS, 23 using with arguments and - (unary operator), 155–157 functions, 166–167 + (unary operator), 156–157 * character, using as wildcard, 28–29 _ (underscore) ? character, using as wildcard, 28–29 PEP 8’s naming conventions, [:] syntax, using, 104 60–61 < comparison operator, 337 as prefix for methods and <= comparison operator, 337 attributes, 291–292 > comparison operator, 337 private prefix, 81 >= comparison operator, 337 using with _spaces attribute, 290 -> (arrow), using with type hints, 191 using with dunder methods, 120 \ (backslash) using with private attributes and purpose of, 18 methods, 283 using with strings, 95 using with WizCoin class, 279 : (colon), using with lists, 97–98, 104 , (comma), including in single-item A tuples, 150 abcTraceback.py program, saving, 4 - (dash), using with command line __abs__() numeric dunder arguments, 25 method, 328 $ (dollar sign), using in macOS, 23 absolute versus relative paths, 20–21 . (dot), using with commands, 31 __add__() numeric dunder method, 327 -- (double dash), using with command addToTotal() function, creating, line arguments, 25 172–173 algebra for big O, 236 base class, relationship to algorithm analysis. -
451 Angular CLI, 77, 412 Component, 89 Detection, 398–399 Http Client, 320–321 Module System, 119 Deployment, 130 Ex100
Index A AngularJS vs. Angular Angular JavaScript using JavaScript CLI, 77, 412 engines, 18 component, 89 platform, 17 detection, 398–399 semantic versioning, 16–17 Http client, 320–321 shims and polyfills, 18 module system, 119 controllers and components, 22 deployment, 130 dependency and constructor ex100, 123–126, 128–129 injection, 22–23 feature module, 122–123 forms, 24 Node commands, 131 modules, 21 root module, 121 module system, 116 routing module, 122 scope, controllers, and components, 24 shared module, 123 templates, 25 Start project, 120–121 Annotations, 91 pipes app.component.spec.ts, 412 combining date formats, 388 Application component, 89 currency, 386 Asynchronous data streams date, 386 event-based reactive programs, 291 json, 388 observable sequences, 292 lowercase, 385 observers, 292–294 percentage, 386 operators predefined date formats, 387 buffer, 300 shortdate, 386 debounce, 302–303 UK pound currency, 386 distinct, 304 uppercase, 385 filter, 304 variety of, 388, 390 from, 298 uses observables, 310 interval, 298 451 © Mark Clow 2018 M. Clow, Angular 5 Projects, https://doi.org/10.1007/978-1-4842-3279-8 INDEX Asynchronous data streams (cont.) Command line interface (CLI) map, 301 bootstrapping, 84–85 of (Was just), 299 compilation, 86 range, 299 compile errors, 82 repeat, 299 creating project, 78–79 scan, 301 file watcher and web server, 84 share, 306–307 modifying project, 81 take, 305 options, 85 timer, 300 root folder, 80 subscription, 295 runtime errors, 82 Asynchronous JavaScript and XML (AJAX) source code, 80 callbacks, 6 Component(s) encoding, 7–8 child, 159–160 HAL and HATEOAS, 8–10 class, 97 JSON and XML, 5 class life cycle promises, 6 constructor vs. -
Less Code, More Fun
KOTLIN LESS CODE, MORE FUN Speaker notes Michael Fazio - @faziodev + 1 Speaker notes + 2 . 1 Speaker notes I work here! 2 . 2 Speaker notes + 3 . 1 Speaker notes + 3 . 2 Speaker notes + 3 . 3 Speaker notes + 3 . 4 3 . 5 WHAT IS... Speaker notes First unveiled in 2011 (after being in dev for a year) Open-sourced in 2012 Version 1.0 released on February 15th, 2016 JetBrains said most languages were lacking the features they wanted Except Scala, but it was slow to compile JetBrains hopes to drive IntelliJ sales 4 . 1 "STATICALLY TYPED PROGRAMMING LANGUAGE FOR MODERN MULTIPLATFORM APPLICATIONS" 4 . 2 STATICALLY TYPED val numbers: List<Int> = listOf(1, 4, 7, 10, 23) enum class Sport { Baseball, Football, Soccer, Basketball } data class Team(val city: String, val teamName: String, val sport: Spo Speaker notes Staticallyval teamtyped: = Team("Milwaukee", "Brewers", Sport.Baseball) Know type of variable at compile time Java C, C++, C# Kotlin uses type inference Type system can figure the type out Don't always have to specify Will warn if not clear Modern: Concise code Lots of features 4 . 3 MULTI-PLATFORM Speaker notes First-class language on Android Interoperable with JVM Transpile Kotlin into JavaScript Compile native code (without VM) Windows Linux MacOS iOS Android WebAssembly 4 . 4 100% JAVA INTEROPERABILITY import io.reactivex.Flowable import io.reactivex.schedulers.Schedulers Flowable .fromCallable { Thread.sleep(1000) // imitate expensive computation "Done" } .subscribeOn(Schedulers.io()) .observeOn(Schedulers.single()) .subscribe(::println, Throwable::printStackTrace) Speaker notes Call existing Java libraries Use Java classes Can call Kotlin classes from Java May need a bit of tweaking 4 . -
If We Dont Declare Keyword Static
If We Dont Declare Keyword Static If expositive or harborless Thornie usually miching his inby brabbling super or predestinated stingingly and theatrically, how unruffled is Daren? Rube puke thoughhis Akkadian Peyton comps induing unshakably, his incomprehensiveness but demulcent Harcourt preappoint. never specialise so outlandishly. Inmost and rebel Aloysius quintuplicating almost suspiciously, Factory methods that scope for data besides the instantiation until recently and useful to be called from the stack overflow the static serve any developer should declare static if we dont need dark matter Java and scope, if we dont declare keyword static. If we dont need it into a nonthrowing method if my own risk of indexing, if we dont declare keyword static fields or auto variable? Then we dont want to declaration at the keyword in the namespace. Like declaring a declaration in my name, declare them the struct static methods are not supported in their intended use is. Suppose you dont need it becomes available in many issues with a keyword? Dm hold data field does hold distinct value you if we dont declare keyword static, but can be striving to. So if you declare more memory is declared locally in this keyword was good style guide to. If we declare two different keywords used to declaring multiple interfaces. The declaration to declare methods if you dont want to use the different keywords used with? Svalbard and remember that keyword, log stuff exported by making a functional, if we dont declare static keyword in scope of. The result in java is if they use a c compiler you if we dont declare static keyword in java, we dont want. -
Groovy Basicsbasics
GroovyGroovy BasicsBasics SangSang ShinShin JPassion.comJPassion.com ““LearnLearn withwith Passion!”Passion!” 1 Topics • What is and Why Groovy? • Groovy Syntax • Differences from Java • Refactoring Java code into Groovy code • Inter-operating with Java • Groovy Ecosystem 2 WhatWhat isis && WhyWhy Groovy?Groovy? What is Groovy? • Dynamic, objected oriented, scripting language for JVM • Seamless integration with Java > Designed with Java in mind from the beginning (unlike other scripting languages) > Easy to learn for Java programmers • Borrowed language features from Ruby, Python, Smalltalk 4 Why Groovy over Other Scripting Languages? • Groovy is a dynamic language “specifically” designed for Java platform > Leverage the benefit of JVM • Groovy provides an effortless transition from Java > Groovy code, when compiled, generated Java bytecode > Existing Java code works in Groovy environment “as it is” basis > Incremental change is possible, in fact, recommended (when you plan to migrate existing Java code to Groovy) 5 Groovy IS Java (or BETTER Java) • Provides syntactic sugar > Easy and fun to code (like Ruby) • Provides new language features over Java > Closure (Java 8 now supports closure through Lambda) > Meta-programming • Provides easier development environment > Scripting > Combines compilation and execution into a single step > Shell interpreter 6 LabLab ExerciseExercise 0:0: InstallInstall GroovyGroovy ExerciseExercise 1:1: GroovyGroovy isis JavaJava 5610_groovy_basics.zip5610_groovy_basics.zip 7 WhyWhy GroovyGroovy (or(or Scala)?Scala)?