Raw Notes on the Ruby Language
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18-Variables.Pdf
Mehran Sahami Handout #18 CS 106A October 12, 2007 Variables, variables, everywhere… Based on a handout by Patrick Young. Local Variables Local variables are created local to the method (or the block—see “Block Scope” section below) in which they are defined. They are destroyed when execution of the method has been completed. Local variables can only be accessed from within the method in which they are declared. Because of their transient nature, local variables cannot store persistent information about an object between method calls. Local Variables Example Consider, for example, the following snippet of code. class AnExample extends ConsoleProgram { public void methodOne { int a = readInt("Enter a: "); println("a = " + a); } public void methodTwo { int b = a; // BUG!: cannot refer to variable a in methodOne println("b = " + b); } } The variables a and b are local variables declared within different methods in the class AnExample . Because these variables are local variables, a can only be referred to within methodOne and variable b can only be accessed within methodTwo . Our attempt to initialize b using the value of a is illegal, as code in methodTwo cannot access local variables from methodOne or any other method. Because local variable values do not persist after their containing method has completed, the variable a will be destroyed when methodOne has completed execution. The next time methodOne is called, a new variable a will be created. Block Scope While we typically think of local variables as local to a particular method, in Java local variables are actually local to a block of code. While a method defines a block of code (since the opening and closing braces of the method define a block), for and while loops, if -statements, and other constructs are also considered blocks of code. -
Preview Objective-C Tutorial (PDF Version)
Objective-C Objective-C About the Tutorial Objective-C is a general-purpose, object-oriented programming language that adds Smalltalk-style messaging to the C programming language. This is the main programming language used by Apple for the OS X and iOS operating systems and their respective APIs, Cocoa and Cocoa Touch. This reference will take you through simple and practical approach while learning Objective-C Programming language. Audience This reference has been prepared for the beginners to help them understand basic to advanced concepts related to Objective-C Programming languages. Prerequisites Before you start doing practice with various types of examples given in this reference, I'm making an assumption that you are already aware about what is a computer program, and what is a computer programming language? Copyright & Disclaimer © Copyright 2015 by Tutorials Point (I) Pvt. Ltd. All the content and graphics published in this e-book are the property of Tutorials Point (I) Pvt. Ltd. The user of this e-book can retain a copy for future reference but commercial use of this data is not allowed. Distribution or republishing any content or a part of the content of this e-book in any manner is also not allowed without written consent of the publisher. We strive to update the contents of our website and tutorials as timely and as precisely as possible, however, the contents may contain inaccuracies or errors. Tutorials Point (I) Pvt. Ltd. provides no guarantee regarding the accuracy, timeliness or completeness of our website or its contents including this tutorial. If you discover any errors on our website or in this tutorial, please notify us at [email protected] ii Objective-C Table of Contents About the Tutorial .................................................................................................................................. -
Algorithms and Data Structures Lecture 11: Symbol Table ADT
cs2010: algorithms and data structures Lecture 11: Symbol Table ADT Vasileios Koutavas School of Computer Science and Statistics Trinity College Dublin Algorithms ROBERT SEDGEWICK | KEVIN WAYNE 3.1 SYMBOL TABLES ‣ API ‣ elementary implementations Algorithms ‣ ordered operations FOURTH EDITION ROBERT SEDGEWICK | KEVIN WAYNE http://algs4.cs.princeton.edu 3.1 SYMBOL TABLES ‣ API ‣ elementary implementations Algorithms ‣ ordered operations ROBERT SEDGEWICK | KEVIN WAYNE http://algs4.cs.princeton.edu Symbol tables Key-value pair abstraction. ・Insert a value with specified key. ・Given a key, search for the corresponding value. Ex. DNS lookup. ・Insert domain name with specified IP address. ・Given domain name, find corresponding IP address. domain name IP address www.cs.princeton.edu 128.112.136.11 www.princeton.edu 128.112.128.15 www.yale.edu 130.132.143.21 www.harvard.edu 128.103.060.55 www.simpsons.com 209.052.165.60 key value 3 Symbol table applications application purpose of search key value dictionary find definition word definition book index find relevant pages term list of page numbers file share find song to download name of song computer ID financial account process transactions account number transaction details web search find relevant web pages keyword list of page names compiler find properties of variables variable name type and value routing table route Internet packets destination best route DNS find IP address domain name IP address reverse DNS find domain name IP address domain name genomics find markers DNA string known positions file system find file on disk filename location on disk 4 Symbol tables: context Also known as: maps, dictionaries, associative arrays. -
A First Course to Openfoam
Basic Shell Scripting Slides from Wei Feinstein HPC User Services LSU HPC & LON [email protected] September 2018 Outline • Introduction to Linux Shell • Shell Scripting Basics • Variables/Special Characters • Arithmetic Operations • Arrays • Beyond Basic Shell Scripting – Flow Control – Functions • Advanced Text Processing Commands (grep, sed, awk) Basic Shell Scripting 2 Linux System Architecture Basic Shell Scripting 3 Linux Shell What is a Shell ▪ An application running on top of the kernel and provides a command line interface to the system ▪ Process user’s commands, gather input from user and execute programs ▪ Types of shell with varied features o sh o csh o ksh o bash o tcsh Basic Shell Scripting 4 Shell Comparison Software sh csh ksh bash tcsh Programming language y y y y y Shell variables y y y y y Command alias n y y y y Command history n y y y y Filename autocompletion n y* y* y y Command line editing n n y* y y Job control n y y y y *: not by default http://www.cis.rit.edu/class/simg211/unixintro/Shell.html Basic Shell Scripting 5 What can you do with a shell? ▪ Check the current shell ▪ echo $SHELL ▪ List available shells on the system ▪ cat /etc/shells ▪ Change to another shell ▪ csh ▪ Date ▪ date ▪ wget: get online files ▪ wget https://ftp.gnu.org/gnu/gcc/gcc-7.1.0/gcc-7.1.0.tar.gz ▪ Compile and run applications ▪ gcc hello.c –o hello ▪ ./hello ▪ What we need to learn today? o Automation of an entire script of commands! o Use the shell script to run jobs – Write job scripts Basic Shell Scripting 6 Shell Scripting ▪ Script: a program written for a software environment to automate execution of tasks ▪ A series of shell commands put together in a file ▪ When the script is executed, those commands will be executed one line at a time automatically ▪ Shell script is interpreted, not compiled. -
Hardware Based Compression in Ceph OSD with BTRFS
Hardware Based Compression in Ceph OSD with BTRFS Weigang Li ([email protected]) Tushar Gohad ([email protected]) Data Center Group Intel Corporation 2016 Storage Developer Conference. © Intel Corp. All Rights Reserved. Credits This work wouldn’t have been possible without contributions from – Reddy Chagam ([email protected]) Brian Will ([email protected]) Praveen Mosur ([email protected]) Edward Pullin ([email protected]) 2 2016 Storage Developer Conference. © Intel Corp. All Rights Reserved. Agenda Ceph A Quick Primer Storage Efficiency and Security Features Offload Mechanisms – Software and Hardware Compression in Ceph OSD with BTRFS Compression in BTRFS and Ceph Hardware Acceleration with QAT PoC implementation Performance Results Key Takeaways 3 2016 Storage Developer Conference. © Intel Corp. All Rights Reserved. Ceph Open-source, object-based scale-out storage system Software-defined, hardware-agnostic – runs on commodity hardware Object, Block and File support in a unified storage cluster Highly durable, available – replication, erasure coding Replicates and re-balances dynamically 4 Image source: http://ceph.com/ceph-storage 2016 Storage Developer Conference. © Intel Corp. All Rights Reserved. Ceph Scalability – CRUSH data placement, no single POF Enterprise features – snapshots, cloning, mirroring Most popular block storage for Openstack use cases 10 years of hardening, vibrant community 5 Source: http://www.openstack.org/assets/survey/April-2016-User-Survey-Report.pdf 2016 Storage Developer Conference. © Intel Corp. All Rights Reserved. Ceph: Architecture OSD OSD OSD OSD OSD btrfs xfs ext4 POSIX Backend Backend Backend Backend Backend Bluestore KV DISK DISK DISK DISK DISK Commodity Servers M M M 6 2016 Storage Developer Conference. -
Java Static Keyword
This page was exported from - TechnicalStack Export date: Sun Sep 26 13:56:23 2021 / +0000 GMT Java static keyword Java static keyword The static keyword in java is used for memory management mainly. We can apply java static keyword with variables, methods, blocks and nested class. The static keyword belongs to the class than instance of the class. The static can be: - variable (also known as class variable) - method (also known as class method) - block - nested class 1) Java static variable If you declare any variable as static, it is known static variable. - The static variable can be used to refer the common property of all objects (that is not unique for each object) e.g. company name of employees,college name of students etc. - The static variable gets memory only once in class area at the time of class loading. Advantage of static variable It makes your program memory efficient (i.e it saves memory). Understanding problem without static variable class Student{ int rollno; String name; String college="ITS"; } Suppose there are 500 students in my college, now all instance data members will get memory each time when object is created.All student have its unique rollno and name so instance data member is good.Here, college refers to the common property of all objects.If we make it static,this field will get memory only once. Java static property is shared to all objects. Example of static variable //Program of static variable class Student8{ int rollno; String name; static String college ="ITS"; Student8(int r,String n){ -
XAVIER CANAL I MASJUAN SOFTWARE DEVELOPER - BACKEND C E N T E L L E S – B a R C E L O N a - SPAIN
XAVIER CANAL I MASJUAN SOFTWARE DEVELOPER - BACKEND C e n t e l l e s – B a r c e l o n a - SPAIN EXPERIENCE R E D H A T / K i a l i S OFTWARE ENGINEER Barcelona / Remote Kiali is the default Observability console for Istio Service Mesh deployments. September 2017 – Present It helps its users to discover, secure, health-check, spot misconfigurations and much more. Full-time as maintainer. Fullstack developer. Five people team. Ownership for validations and security. Occasional speaker. Community lead. Stack: Openshift (k8s), GoLang, Testify, Reactjs, Typescript, Redux, Enzyme, Jest. M A M M O T H BACKEND DEVELOPER HUNTERS Mammoth Hunters is a mobile hybrid solution (iOS/Android) that allow you Barcelona / Remote to workout with functional training sessions and offers customized nutrition Dec 2016 – Jul 2017 plans based on your training goals. Freelancing part-time. Evangelizing test driven development. Owning refactorings against spaghetti code. Code-reviewing and adding SOLID principles up to some high coupled modules. Stack: Ruby on Rails, Mongo db, Neo4j, Heroku, Slim, Rabl, Sidekiq, Rspec. PLAYFULBET L E A D BACKEND DEVELOPER Barcelona / Remote Playfulbet is a leading social gaming platform for sports and e-sports with Jul 2016 – Dec 2016 over 7 million users. Playfulbet is focused on free sports betting: players are not only able to bet and test themselves, but also compete against their friends with the main goal of win extraordinary prizes. Freelancing part-time. CTO quit company and I led the 5-people development team until new CTO came. Team-tailored scrum team organization. -
Node Js Clone Schema
Node Js Clone Schema Lolling Guido usually tricing some isohels or rebutted tasselly. Hammy and spacious Engelbert socialising some plod so execrably! Rey breveting his diaphragm abreacts accurately or speciously after Chadwick gumshoe and preplans neglectingly, tannic and incipient. Mkdir models Copy Next felt a file called sharksjs to angle your schema. Build a Twitter Clone Server with Apollo GraphQL Nodejs. To node js. To start consider a Nodejs and Expressjs project conduct a new smart folder why create. How to carriage a JavaScript object Flavio Copes. The GitHub repository requires Nodejs 12x and Python 3 Before. Dockerizing a Nodejs Web Application Semaphore Tutorial. Packagejson Scripts AAP GraphQL Server with NodeJS. Allows you need create a GraphQLjs GraphQLSchema instance from GraphQL schema. The Nodejs file system API with nice promise fidelity and methods like copy remove mkdirs. Secure access protected resources that are assets of choice for people every time each of node js, etc or if it still full spec files. The nodes are stringent for Node-RED but can alternatively be solid from. Different Ways to Duplicate Objects in JavaScript by. Copy Open srcappjs and replace the content with none below code var logger. Introduction to Apollo Server Apollo GraphQL. Git clone httpsgithubcomIBMcrud-using-nodejs-and-db2git. Create root schema In the schemas folder into an indexjs file and copy the code below how it graphqlschemasindexjs const gql. An api requests per user. Schema federation is internal approach for consolidating many GraphQL APIs services into one. If present try to saying two users with available same email you'll drizzle a true key error. -
GNUPG Open Source Encryption on HP Nonstop
GNUPG Open Source Encryption on HP NonStop Damian Ward NonStop Solutions Architect / BITUG Vice Chairman Confidential Introduction What am I going to talk about today • About Me • About VocaLink • History of encryption • PGP to GNUPG • PGP encryption walkthrough • Installing GNUPG • Use Case • Questions..? Please feel free to ask as we go through the presentation. Confidential 2 Introduction About your presenter • Damian Ward • 20+ years HP NonStop and Payments experience • Career spanning: − Operations, Application Programming, System Management, Programme Management, Technical Specialist, Solutions Architect, Enterprise Architect, Infrastructure Architect • Specialities: − HP NonStop systems and architecture, Enterprise Architecture, Encryption, Availability Management, ATM Systems, Payments Processing, Capacity Planning, System modelling, Fraud, Mobile and Internet technologies, Programming, Emerging Technologies and Robotics • BITUG Vice Chairman 2011 • BITUG Chairman 2012 Confidential 3 Introduction VocaLink: cards processing landscape Direct connection to in house processing system Indirect ATM acquirer and card issuer connection (via VocaLinkCSB) FIS Connex Advantage Connections to Mobile Switch with resillient Operators Indirect ATM connection (via third telecommunication party processor) connections to each customer Connections to Direct connection overseas to Post Office via TNS CSB schemes and systems ATM and POS international banks acquiring and issuing connections via gateway connections to international schemes Confidential -
CS 61A A&S Section 3.0 Object-Oriented Programming
CS 61A A&S Section 3.0 Object-Oriented Programming | Above the line view This document should be read before Section 3.1 of the text. A second document, \Object-Oriented Programming | Below the line view," should be read after Section 3.1 and perhaps after Section 3.2; the idea is that you first learn how to use the object-oriented programming facility, then you learn how it's implemented. Object-oriented programming is a metaphor. It expresses the idea of several independent agents inside the computer, instead of a single process manipulating various data. For example, the next programming project is an adventure game, in which several people, places, and things interact. We want to be able to say things like \Ask Fred to pick up the potstickers." (Fred is a person object, and the potstickers are a thing object.) Programmers who use the object metaphor have a special vocabulary to describe the components of an object-oriented programming (OOP) system. In the example just above, \Fred" is called an instance and the general category \person" is called a class. Programming languages that support OOP let the programmer talk directly in this vocabulary; for example, every OOP language has a “define class" command in some form. For this course, we have provided an extension to Scheme that supports OOP in the style of other OOP languages. Later we shall see how these new features are implemented using Scheme capabilities that you already understand. OOP is not magic; it's a way of thinking and speaking about the structure of a program. -
Bash Guide for Beginners
Bash Guide for Beginners Machtelt Garrels Garrels BVBA <tille wants no spam _at_ garrels dot be> Version 1.11 Last updated 20081227 Edition Bash Guide for Beginners Table of Contents Introduction.........................................................................................................................................................1 1. Why this guide?...................................................................................................................................1 2. Who should read this book?.................................................................................................................1 3. New versions, translations and availability.........................................................................................2 4. Revision History..................................................................................................................................2 5. Contributions.......................................................................................................................................3 6. Feedback..............................................................................................................................................3 7. Copyright information.........................................................................................................................3 8. What do you need?...............................................................................................................................4 9. Conventions used in this -
Lecture 17 the Shell and Shell Scripting Simple Shell Scripts
Lecture 17 The Shell and Shell Scripting In this lecture • The UNIX shell • Simple Shell Scripts • Shell variables • File System commands, IO commands, IO redirection • Command Line Arguments • Evaluating Expr in Shell • Predicates, operators for testing strings, ints and files • If-then-else in Shell • The for, while and do loop in Shell • Writing Shell scripts • Exercises In this course, we need to be familiar with the "UNIX shell". We use it, whether bash, csh, tcsh, zsh, or other variants, to start and stop processes, control the terminal, and to otherwise interact with the system. Many of you have heard of, or made use of "shell scripting", that is the process of providing instructions to shell in a simple, interpreted programming language . To see what shell we are working on, first SSH into unix.andrew.cmu.edu and type echo $SHELL ---- to see the working shell in SSH We will be writing our shell scripts for this particular shell (csh). The shell scripting language does not fit the classic definition of a useful language. It does not have many of the features such as portability, facilities for resource intensive tasks such as recursion or hashing or sorting. It does not have data structures like arrays and hash tables. It does not have facilities for direct access to hardware or good security features. But in many other ways the language of the shell is very powerful -- it has functions, conditionals, loops. It does not support strong data typing -- it is completely untyped (everything is a string). But, the real power of shell program doesn't come from the language itself, but from the diverse library that it can call upon -- any program.