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How to Become a Software Architect?

Indeed, when an individual decides to build a career in the Software Development field, there is one thing that always comes in his mind – How the career will progress & What will be future opportunities? Although, there are various worthwhile career opportunities after spending an adequate amount in the tech domain. And among all those options, one of the most considerable and impactful profile is Software Architect! As per the reports, Software Architect is one of the most demanding jobs in recent years, and considering the expansion of the IT industry (particularly the Development domain), the future of Software Architects seems bright!!

Before moving further, let’s take a look at the question – Who is a Software Architect? A Software Architect is an IT professional who has expertise in Software Development, and he collaborates with various teams for the overall effective execution of the processes whether it be designing or development or implementation of software solutions. In general, a Software Architect makes crucial high-level software design choices and work on various aspects such as determine required technologies for the development team, carry out technical standards, etc. to build worthwhile software systems or solutions as per the needs of the client. A Software Architect can be responsible for various roles & responsibilities in an organization such as:

Communicates with clients to identify software requirements and other needs.
Comes up with optimal technical standards, tools, processes, etc. for the project.
Leads the team of developers and distributes the development tasks accordingly.
Collaborates with other teams, end-users, etc. to deliver high-quality software solutions.
Works on Code Reviewing, Documentation, Troubleshooting, and other related areas, etc.

As of now, you have already become aware of the Software Architect job profile. Now let’s get back to the main concern – How to Become a Software Architect? And with the same concern, let’s go through the complete roadmap that you need to follow to build a successful & worthwhile career in Software Architect domain:

1. Start with the Academics

If you’re considering becoming a Software Architect, the first and foremost thing you need to do – get enrolled yourself for the relevant study program. You can look forward to possessing a Bachelor’s or Master’s degree in Computer Science / Information Technology or other related domain as it will not only make your fundamentals stronger but will also make you eligible for many ravishing career opportunities in various IT giants. Moreover, along with the degree or educational background, you can opt for several specific training programs, boot camps, etc. as well to get more proficiency & exposure in the Software Architect domain.

2. Get Proficient with Programming Languages

To start your career as a Software Architect, you’re always required to have a sound knowledge of programming languages & frameworks. As a Software Architect, you’re not solely responsible to do coding the entire day but you’re required to lead the team of developers, collaborate with other teams, review code, etc. hence you must have a thorough understanding of programming concepts and paradigms. Meanwhile, you can start to learn programming with various demanding programming languages such as C++, Python, Ruby, Go, etc. Also, you can opt to build several minor projects and can participate in various coding challenges to boost your programming skills.

3. Enter the IT world as a Software Developer

As mentioned above, Software Architect is not an entry-level career domain and can be considered as one of the succeeding positions of a Software Developer, hence you’re strongly recommended to gain an adequate amount of hands-on experience on a developer’s profile. Meanwhile, apart from the coding skills, you need to understand & work upon several other crucial aspects as a developer to become a Software Architect such as teamwork & task allotment, SDLC phases of the project, requirement analysis from clients, etc. It will help you to understand the entire functioning of the development field from designing to deployment that will further make it easier for you to get into the Software Architect domain.

4. Gain Sound Knowledge of System Design, DevOps, etc.

Once you’ll get entered into the Software Development field and become proficient with programming languages & frameworks, now it’s time for you to work on your goal (i.e., to become a Software Architect) and accordingly learn & upgrade your skills to achieve the target. Needless to say, a Software Architect is responsible for many tasks hence, you’re required to get familiar with several crucial domains such as System Design, Development Operations or DevOps, etc. You need to have a deep understanding of Design Patterns & Architecture, Fundamentals of Data Modeling, Unified Modeling Language (UML), and other related concepts to start your career as a Software Architect.

5. Get Relevant Certifications

Furthermore, let’s discuss several renowned certifications for aspiring Software Architects. These certifications not only validates your skills & learnings but also offer you to gain some practical exposure. Apart from this, possessing these certifications can help you to get various career opportunities in IT giants. Moreover, there are numerous prestigious certifications that you can consider to obtain as per your niche whether it be Solution, Enterprise, and Domain Architecture. Some of these certifications are – ISAQB Software Architecture – Foundation LeveL, CITA-P: Certified IT Architect, ITIL Master (Axelos), AZURE Architect certification, and many more.

6. Work On Required Soft Skills

How can we forget that?? Indeed, having appropriate & relevant soft skills are as crucial as having technical skills to become a successful Software Architect. Firstly, you’re required to have good communication skills as you have to collaborate with clients, developers, other teams for the smooth functioning of the processes. Moreover, you need to have good problem-solving skills to come with innovative & optimal solutions for the problems. Apart from these, you’re required to work on several other crucial soft-skills such as Time Management, Leadership, Team Player, etc. for being a proficient Software Architect.

So, these are several major approaches that you need to follow to become a Software Architect. Indeed, the career path of becoming a Software Architect is not so easy and it may take you a few years of experience to get into the particular field, but it is needless to say that every step of this journey has its worth. Meanwhile, there are several recommended books mentioned below that can help you to become a Software Architect:

Fundamentals of Software Architecture
Software Architecture in Practice
Domain-Driven Design: Tackling Complexity in the Heart of Software
Patterns of Enterprise Application Architecture

Undoubtedly, the Software Architect job profile has a lot more to offer you. Now, what are you waiting for? Do follow the above-mentioned approaches and start to learn the required skills to become a successful Software Architect!!

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7 Best Languages to Learn IoT Development in 2020

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Have you ever thought of building a single application to access & control all your home applications or a device that can help you to monitor & early detection of any unusual change in your body, etc…?? If yes, then the Internet of Things (IoT) is the right domain for you!! Statistically, there will be more than 25 billion IoT devices by the year 2021 which signifies that undoubtedly, IoT is the next big thing in the upcoming years. However, like other tech domains, the first thing you need to do is get proficient with a relevant programming language to learn IoT Development.

When we talk about the Internet of Things (IoT), it is concerned with the network of physical devices that are embedded with several technologies in order to connect, communicate and share the data with each other over the network. The major components of the Internet of Things (IoT) are connectivity, integration, cloud computing, sensing, & various others and the technology has its applications in multiple areas whether it be Smart IoT devices for Homes, Health Care, Automation, Retail, etc. Now, when it comes to picking out a Programming Language for IoT Development, there are several prominent factors that must be considered such as compatibility with platform & tools, efficiency, cost of development, etc.

Though as there are numerous programming languages available, it becomes quite difficult to find out the relevant and worthwhile one for the IoT Development. No worries, here in this article, we’ll let you know about several most-recommended programming languages that you can opt to learn IoT Development in 2020:

1. JAVA

When it comes to IoT Development, JAVA stands out among the most popular programming languages. One of the prominent features that make JAVA favorable for the Internet of Things (IoT) Development is Write Once, Run Anywhere concept which implies that the compiled JAVA code can run on any platform that supports the language without compiling it again. In general, the JAVA codes are compiled to byte code that can run on any JAVA Virtual Machine conveniently. Moreover, the object-oriented language allows you to build the applications compatible for both – Edge nodes as well as Cloud. Furthermore, the languages come up with various other renowned features such as an extensive built-in library, highly interoperable, etc. beneficial for the IoT Development.

2. Python

Python is another most-recommended programming language compatible for the IoT Development. It is an interpreted language that supports the programming standards of object-oriented programming as well as functional & structured programming. The high-level programming language has an easier syntax and better code readability that makes it one of the most preferred languages for IoT by the developers. Also, the language can work on various platforms such as Windows, Linux, etc. and can be integrated with other languages such as C++, Java, etc. conveniently. Moreover, the language has rich library support, large community support, and various other features, and also it is much suitable for data-intensive applications.

3. C

How can we forget this much-acclaimed programming language!! C can be considered as one of the most widely used programming languages in the Internet of Things (IoT) world. The middle-Level programming language allows you to understand the underlying architecture of programming that provides the required flexibility to the IoT Developers. Moreover, the language has several other prominent features also such as portability, rich library, and many more. Furthermore, the language is pretty much compatible with the micro-controllers required for the IoT devices. However, it requires more effort and time as well to learn C Language effectively due to its not-so-easy syntax and layered architecture.

4. LUA

However, LUA is not one of the usual names in the computer programming word but when it comes to IoT Development, it has already made its strong presence among the developers. LUA is a general-purpose, high-level programming language that is specifically designed for embedded purposes. The extensible procedural language is aimed to support data description facilities and it is required to be embedded in a host client for successful functioning. Moreover, LUA comes up with its most preferred framework Node.lua built on a lightweight LUA interpreter that helps the developers to create IoT- based applications and various other enriching features such as better efficiency, portability, etc.

5. Golang

Golang, sometimes referred to as Go, is also one of those best languages that can be taken into consideration for IoT Development. In general, Golang is an open-source statically typed programming language, developed by Robert Griesemer, Rob Pike, and Ken Thompson at Google. The language offers several prominent features such as inbuilt concurrency (goroutines & channels) and the ability for the maximum usage of the hardware that makes it more compatible and relevant for the IoT development. Furthermore, the language provides several other crucial features also such as the rich standard library, dynamic-typing capability, etc. that can also be considered by the developers.

6. PHPoC

If you’re familiar with PHP (Hypertext Preprocessor) Language then to relate with the PHPoC (PHP on Chip) is not a big deal for you!! Meanwhile, PHPoC (PHP on Chip) is a programming language (based on PHP Language) and an IoT hardware platform. Even the syntax of PHPoC is almost similar to the PHP language. However, it can be considered that PHPoC is not only a web development language but also a general-purpose programming language compatible and suitable for IoT. Moreover, apart from the core PHP functions, PHPoC also includes several additional functions like SPI, UART, RTC, and various others beneficial for the IoT Development.

7. Swift

Last but not least – Swift!! If we talk about the language introduction – Swift is a general-purpose, multi-paradigm programming language that is specifically designed to create applications for iOS, iPadOS, macOS, watchOS, and tvOS. The language comes up with several prominent features such as powerful error handling, functional programming patterns, fast & secure, and many more. However, as mentioned above that Swift is particularly concerned with the development of applications for Apple’s devices so if you’re looking forward to doing IoT development for these particular platforms such as iOS, macOS, etc. then you’re strongly recommended to opt for Swift otherwise you can go with other languages as well.

So these are several programming languages that you can take into consideration to learn IoT Development. Meanwhile, you can opt for a language (from the above-mentioned list or other than that) based on your own preferences, for example – if you’re looking for a language for IoT development with the easier syntax you can go with Python or if want to learn IoT for iOs & macOS devices you can opt for Swift, and so on. However, whichever language you’d choose, you’re required to do hard work with all the dedication and consistency to accomplish your goals!!

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REDIS Beginners Tutorial

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Redis is an open-source BSD licensed advanced key-value store in-memory NoSQL database. Redis stands for REmote DIctonary Server. It is also referred to as a data structure server, since the keys can contain strings, hashes, lists, sets & sorted sets, etc. Redis can be used as Database (persist data), Memory cache (temporary store to improve performance) and also it can be be used as message broker.

Redis has two-parts, Redis server, and Redis client (Redis CLI). Redis servers can be interacted using the command-line tool Redis CLI (Command Line Interface).

How to run REDIS on Windows 10

Step1: Make Windows Power Shell as the default shell, then open Windows Power shell as Administrator to enable Windows System for Linux(WSL) Use below command to enable it:

Enable-WindowsOptionalFeature -Online -FeatureName Microsoft-Windows-Subsystem-Linux

Step2: Reboot the windows after making these changes.

Step3: Download and install one of the supported Linux distros from the Micro Soft Store (e.g. RAFT WSL)

Install And Run Redis:

Step 1: Launch the distros (RAFT WSL) using it install Ubuntu

Step 2: you’ll need to wait for initialization and create a login upon first use.

Step3: Run below set of command to install redis-server and redis-cli

> sudo apt-get update
> sudo apt-get upgrade
> sudo apt-get install redis-server
> redis-cli -v

Step4: To make sure redis-server is running

sudo service redis-server restart

Step5: Start redis-cli and run below commands.

$ redis-cli 
127.0.0.1:6379> set user:1 "JBT"
127.0.0.1:6379> get user:1
"JBT"

Redis Command

Redis command can be divided into different groups e.g. Connection, Geo, Hashes, Keys, Lists, etc. Each group contains the list of commands used for specific purposes. In this article, we will try to explore some mostly used command in Redis. And we will get to know the purpose of those commands and how they can be used in redis?

Redis Connection

AUTH (Authentication):

Once Redis server is up. It can authenticate the incoming request in any of the two different ways.

Redis ACL system (Not Discussed here)
Using requirepassword option to make Redis server authenticate incoming requests against a given password. And this can be done in two ways.
- Set password from Redis Client using the command
- Pass config file as a parameter while starting the Redis server which has a password in it.

Once connected to Redis Server, set value of key “requirepass” in config for enabling the authentication in Redis Server like below.

127.0.0.1:6379> config get requiredpass
(empty list or set)
127.0.0.1:6379> config set requirepass password
OK
127.0.0.1:6379> config get requiredpass
(error) NOAUTH Authentication required.
127.0.0.1:6379> auth password
OK
127.0.0.1:6379> set name javabeginnerstutorial
OK
127.0.0.1:6379> get name
"javabeginnerstutorial"

Or you can pass config file as a parameter while starting the Redis Server with below content.

requirepass password

Command to start Redis server

redis-server /path/to/configfile/redis.conf

CLIENT SETNAME:

Assigns name to the current connection and the assigned name is displayed in the output of CLIENT LIST command.

127.0.0.1:6379> client setname jbtclient
OK
127.0.0.1:6379> client list
id=3 addr=127.0.0.1:53500 fd=8 name=jbtclient age=395 idle=0 flags=N db=0 sub=0 psub=0 multi=-1 qbuf=26 qbuf-free=32742 obl=0 oll=0 omem=0 events=r cmd=client

Open another redis-cli and run below commands to understand more about client name:

127.0.0.1:6379> client list
id=3 addr=127.0.0.1:53500 fd=8 name=jbtclient age=489 idle=94 flags=N db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=client
id=4 addr=127.0.0.1:53662 fd=9 name= age=28 idle=0 flags=N db=0 sub=0 psub=0 multi=-1 qbuf=26 qbuf-free=32742 obl=0 oll=0 omem=0 events=r cmd=client

CLIENT GETNAME:

Returns the current client name set by CLIENT SETNAME command.

127.0.0.1:6379> client getname
"jbtclient"

CLIENT ID:

This will return current connection client id.

127.0.0.1:6379> client id
(integer) 3

CLIENT LIST

127.0.0.1:6379> client list
id=3 addr=127.0.0.1:53500 fd=8 name=jbtclient age=879 idle=0 flags=N db=0 sub=0 psub=0 multi=-1 qbuf=26 qbuf-free=32742 obl=0 oll=0 omem=0 events=r cmd=client

PING

Returns PONG if no argument is provided, otherwise return a copy of the argument as a bulk. This command is often used to test if a connection is still alive, or to measure latency.

127.0.0.1:6379> ping
PONG
127.0.0.1:6379> ping jbt
"jbt"

SELECT

Select the Redis logical database having the specified zero-based numeric index. New connections always use the database 0, this command cannot be used while using the Redis cluster because the redis cluster only supports zero databases.

127.0.0.1:6379> select 0
OK

Key Group

KEYS

This command returns all keys matching the given pattern. Use this command with care in production with a large database. As it will hamper the performance. (Use keys * to print available keys in REDIS.)

127.0.0.1:6379> keys n*
1) "name"
127.0.0.1:6379>

Supported glob-style patterns:

h?llo matches hello, hallo and hxllo
h*llo matches hllo and heeeello
h[ae]llo matches hello and hallo, but not hillo
h[^e]llo matches hallo, hbllo, … but not hello
h[a-b]llo matches hallo and hbllo

Use to escape special characters if you want to match them verbatim.

EXPIRE

When you want a specific key to be expired after a set amount of time. You can use EXPIRE command. It sets a timeout on the given key. After the timeout has expired, the key will automatically be deleted. A key with an associated timeout is often said to be volatile in Redis terminology. ttl (time-to-live) command can be used to know how long the given key will survive.

If you have set a timeout of 10 second on a key. You can check with ttl the remaining to live for the key.

Expire can returns any of the below value, which has different meaning .

1 if the timeout was set.
0 if key does not exist.
-1 never expires

127.0.0.1:6379> set name "Java Beginners Tutorial"
OK
127.0.0.1:6379> expire name 10
(integer) 1
127.0.0.1:6379> ttl name
(integer) 7
127.0.0.1:6379> set name "Java Beginners Tutorial"
OK
127.0.0.1:6379> ttl name
(integer) -1
127.0.0.1:6379> expire name2 10
(integer) 0

EXISTS

1 if the key exists.
0 if the key does not exist.

127.0.0.1:6379> exists name
(integer) 1
127.0.0.1:6379> exists name2
(integer) 0
127.0.0.1:6379>

MOVE

Move key from the currently selected database to the specified destination database.

Returns:

1 if key was moved.
0 if key was not moved.

127.0.0.1:6379> move name 1
(integer) 1
127.0.0.1:6379> keys name
(empty list or set)
127.0.0.1:6379> select 1
OK
127.0.0.1:6379[1]> keys name
1) "name"
127.0.0.1:6379[1]> get name
"Java Beginners Tutorial"
127.0.0.1:6379[1]>

RENAME

Renames key to new key. It returns an error when key does not exist. If new key already exists it is overwritten

127.0.0.1:6379> rename name jbt
OK
127.0.0.1:6379> get name
(nil)
127.0.0.1:6379> get jbt
"Java Beginners Tutorial"
127.0.0.1:6379> rename jbt name
OK

TTL

Returns the remaining time to live of a key that has a timeout

return value in case of error changed:

The command returns -2 if the key does not exist.
The command returns -1 if the key exists but has no associated expire.

127.0.0.1:6379> expire name 10
(integer) 1
127.0.0.1:6379> ttl name
(integer) 7
127.0.0.1:6379> set name "Java Beginners Tutorial"
OK
127.0.0.1:6379> ttl name2
(integer) -2
127.0.0.1:6379> ttl name
(integer) -1
127.0.0.1:6379>

String Group

GET

Get the value of key. If the key does not exist, the special value nil is returned. An error is returned if the value stored at key is not a string, because it only handles string values.

127.0.0.1:6379> get name
"Java Beginners Tutorial"
127.0.0.1:6379> get name2
(nil)
127.0.0.1:6379>

CONFIGGET

This command is used to read the configuration parameters of a running Redis server.

127.0.0.1:6379> config get *max-*entries
1) "hash-max-ziplist-entries"
2) "512"
3) "stream-node-max-entries"
4) "100"
5) "set-max-intset-entries"
6) "512"
7) "zset-max-ziplist-entries"
8) "128"
127.0.0.1:6379>

MGET

Returns the values of all specified keys. For every key that does not hold a string value or does not exist, the special value nil is returned.

127.0.0.1:6379> MGET name name2
1) "Java Beginners Tutorial"
2) (nil)
127.0.0.1:6379>

GETRANGE

Returns the substring of the string value stored at key, determined by the offsets start and end (both are inclusive).

127.0.0.1:6379> getrange name 0 3
"Java"
127.0.0.1:6379> getrange name -3 -2
"ia"
127.0.0.1:6379> getrange name -3 -1
"ial"
127.0.0.1:6379> getrange name 0 -1
"Java Beginners Tutorial"
127.0.0.1:6379> getrange name 0 25
"Java Beginners Tutorial"
127.0.0.1:6379> getrange name 10 23
"ners Tutorial"
127.0.0.1:6379>

APPEND

It will append given string to value of key and returns the length of string after appending.

127.0.0.1:6379> set framework "Spring"
OK
127.0.0.1:6379> get framework
"Spring"
127.0.0.1:6379> append framework " 5"
(integer) 8
127.0.0.1:6379> get framework
"Spring 5"
127.0.0.1:6379>

SET

Set key to hold the string value. If key already holds a value, it is overwritten, regardless of its type.

Options:

EX seconds — Set the specified expire time, in seconds.
PX milliseconds — Set the specified expire time, in milliseconds.
NX — Only set the key if it does not already exist.
XX — Only set the key if it already exist.
KEEPTTL — Retain the time to live associated with the key.

127.0.0.1:6379> set framework Spring EX 60
OK
127.0.0.1:6379> get framework
"Spring"
127.0.0.1:6379> ttl framework
(integer) 52
127.0.0.1:6379>

MSET

Sets the given keys to their respective values. It replaces existing values with new values.

127.0.0.1:6379> mset framework Spring language Java
OK
127.0.0.1:6379> mget framework language
1) "Spring"
2) "Java"
127.0.0.1:6379>

MSETNX

Sets the given keys to their respective values. It will not perform any operation at all, even if just a single key already exists.

127.0.0.1:6379> msetnx framework Spring frontend Angular
(integer) 0
127.0.0.1:6379> mget name framework frontend
1) "Java Beginners Tutorial"
2) "Spring"
3) (nil)
127.0.0.1:6379>

GETSET

Automatically sets key to value and returns the old value stored at key. Returns an error when key exists but does not hold a string value.

127.0.0.1:6379> set mykey hello
OK
127.0.0.1:6379> getset mykey world
"hello"
127.0.0.1:6379> get mykey
"world"
127.0.0.1:6379>

List Group

LPUSH

Insert all the specified values at the head of the list stored at key. If the key does not exist, it is created as an empty list before performing the push operations. When the key holds a value that is not a list, an error is returned. It returns the length of the list after a successful insert.

127.0.0.1:6379> lpush mylist "World"
(integer) 1
127.0.0.1:6379> lpush mylist "hello"
(integer) 2
127.0.0.1:6379> lpush mylist "JBT"
(integer) 3
127.0.0.1:6379> lpush mylist "Java"
(integer) 4
127.0.0.1:6379> lpush name Spring
(error) WRONGTYPE Operation against a key holding the wrong kind of value
127.0.0.1:6379>

LIDEX

Returns the element at index index in the list stored at key.

127.0.0.1:6379> lindex mylist 0
"hello"
127.0.0.1:6379> lindex mylist 1
"World"
127.0.0.1:6379> lindex mylist 5
(nil)
127.0.0.1:6379>

LLEN

Returns the length of list stored at key. If the key does not exist, it pretended as empty list and returns 0. It returns an error when the value stored at key is not a list.

127.0.0.1:6379> llen mylist
(integer) 4
127.0.0.1:6379> llen mylist2
(integer) 0
127.0.0.1:6379> llen name
(error) WRONGTYPE Operation against a key holding the wrong kind of value
127.0.0.1:6379> get name
"Java Beginners Tutorial"
127.0.0.1:6379>

LPUSHX

Inserts specified values at the head of the list stored at key, only if key already exists and holds a list. In contrary to LPUSH no operation will be performed when key does not yet exist.

127.0.0.1:6379> LPUSHX mylist nodejs
(integer) 5
127.0.0.1:6379> lpushx mylist2 nodejs
(integer) 0
127.0.0.1:6379>

RPUSH

Insert all the specified values at the tail of the list stored at key. If the key does not exist, it is created as an empty list before performing the push operations. When the key holds a value that is not a list, an error is returned. It returns the length of the list after a successful insert.

127.0.0.1:6379> RPUSH mylist "Java Beginners Tutorial" "REDIS"
(integer) 7
127.0.0.1:6379> LRANGE mylist 0 -1
1) "nodejs"
2) "Java"
3) "JBT"
4) "hello"
5) "World"
6) "Java Beginners Tutorial"
7) "REDIS"
127.0.0.1:6379> rpush name JBT
(error) WRONGTYPE Operation against a key holding the wrong kind of value
127.0.0.1:6379> RPUSH mylist2 "JBT"
(integer) 1
127.0.0.1:6379>

RPUSHX

Inserts specified values at the tail of the list stored at key, only if a key already exists and holds a list. In contrary to RPUSH no operation will be performed when the key does not yet exist.

127.0.0.1:6379> rpushx mylist "Spring Boot" "Kotlin"
(integer) 9
127.0.0.1:6379> LRANGE mylist 0 -1
1) "nodejs"
2) "Java"
3) "JBT"
4) "hello"
5) "World"
6) "Java Beginners Tutorial"
7) "REDIS"
8) "Spring Boot"
9) "Kotlin"
127.0.0.1:6379> RPUSHX mylist2 "Kotlin"
(integer) 0
127.0.0.1:6379>

LRANGE

Returns the specified elements of the list stored at key. The offsets start and stop are zero-based indexes.

127.0.0.1:6379> lrange mylist 0 4
1) "nodejs"
2) "Java"
3) "JBT"
4) "hello"
5) "World"
127.0.0.1:6379> lrange mylist 0 -1
1) "nodejs"
2) "Java"
3) "JBT"
4) "hello"
5) "World"
6) "Java Beginners Tutorial"
7) "REDIS"
8) "Spring Boot"
9) "Kotlin"
127.0.0.1:6379>

LINSERT

Inserts element in the list stored at key either before or after the reference value. No operation done when key does not exist.

Returns:

An error is returned when key exists but does not hold a list value.
the length of the list after the insert operation
-1 when the value pivot was not found

127.0.0.1:6379> linsert mylist after Kotlin Angular
(integer) 10
127.0.0.1:6379> lrange mylist 0 -1
 1) "nodejs"
 2) "Java"
 3) "JBT"
 4) "hello"
 5) "World"
 6) "Java Beginners Tutorial"
 7) "REDIS"
 8) "Spring Boot"
 9) "Kotlin"
10) "Angular"
127.0.0.1:6379> linsert mylist before JBT Blog
(integer) 11
127.0.0.1:6379> lrange mylist 0 -1
 1) "nodejs"
 2) "Java"
 3) "Blog"
 4) "JBT"
 5) "hello"
 6) "World"
 7) "Java Beginners Tutorial"
 8) "REDIS"
 9) "Spring Boot"
10) "Kotlin"
11) "Angular"
127.0.0.1:6379> linsert mylist after ANgular React
(integer) -1
127.0.0.1:6379> linsert name before JBT java
(error) WRONGTYPE Operation against a key holding the wrong kind of value
127.0.0.1:6379>

LREM

Removes the first count occurrences of elements equal to element from the list stored at key. The count argument influences the operation in the following ways:

count > 0: Remove elements equal to element moving from head to tail.
count < 0: Remove elements equal to element moving from tail to head.
count = 0: Remove all elements equal to element.

It returns no of elements removed.

127.0.0.1:6379> lrem mylist -1 hello
(integer) 1
127.0.0.1:6379> lrem mylist -2 World
(integer) 1
127.0.0.1:6379> lrem mylist 2 Ja
(integer) 0
127.0.0.1:6379> lrem mylis 0 Java
(integer) 0
127.0.0.1:6379> lrem mylist 0 Java
(integer) 1
127.0.0.1:6379>

LPOP & RPOP

LPOP removes and returns first element in list stored at key
RPOP removes and returns last element in list stored at key

127.0.0.1:6379> lpop mylist
"nodejs"
127.0.0.1:6379> rpop mylist
"Angular"
127.0.0.1:6379>

Queries to find the count of shortest paths in a Tree that contains a given edge

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Given a tree with N vertices numbered from 0 to N – 1, M edges, and Q queries of the form {U, V}, such that there is a direct edge between U and V in the tree. The task for each query is to find all possible shortest paths between any possible unordered pair of vertices from the given tree which contains the edge between the given pair of nodes.

Input: N = 6, M[] ={{0, 1}, {0, 2}, {1, 3}, {3, 4}, {3, 5}}, queries[] = {{1, 3}, {0, 2}}
0
/
1 2
/
3
/
4 5
Output:
9
5
Explanation:
Query 1: The edge (1, 3) lies in the paths {1, 3), (1, 3, 4), (1, 3, 5), (0, 3), (0, 4), (0, 5), (2, 3), (2, 4) and (2, 5).
Query 2: The edge (0, 2) lies in the paths (2, 0), (2, 1), (2, 3), (2, 4) and (2, 5).

Input: N = 6, M[] ={{0, 1}, {0, 2}, {2, 3}, {1, 4}, {1, 5}}, queries[] = {{1, 5}, {0, 2}}
0
/
1 2
/ /
4 5 3
Output:
5
8

Approach: The problem can be solved based on the observation that for any query {U, V}, the shortest path between any pair of nodes in the tree will contain the given edge (U, V) if one of the nodes lie in the subtree of U and the other node lies in the remaining tree. Therefore, the required number of pairs will be:

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Oracle Interview Experience | Campus Placements 2020

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Online Test (150 mins): This round had certain sections. There was an additional constraint that in each section, one had to answer the questions in order. A candidate could not skip questions and re-attempt them later. The sections were based on the following:

Aptitude
DSA concepts
CS courses concepts such as OS, DBMS, OOP
English

Around 200 students appeared for the online test from which approximately 65 were selected for the technical interviews.

Technical Interview 1: Due to coronavirus lockdown, the interviews were held on Zoom.

Explain Multithreading
Advantages/Disadvantages of Multithreaded vs. Single Process programs.
Answer: Multithreaded – Can exploit the parallelism of a task and achieve a speedup. Also, the program can be logically divided into many threads which can then be developed individually. It will also make efficient use of memory and CPU time. However, multithreaded programs are harder to debug, and harder to write.

Single Process programs – Entire program has to be loaded at once, even though it has multiple components some of which will be used seldom. Thus, it leads to a waste of RAM. However, they are much easier to debug.
What will happen if a thread dies?
Answer: The master process must monitor the status of each thread and take appropriate action – abort the program, restart a thread.
Given an array, for every index, compute the product of all elements of the array except the element at that index. Using the division operator is NOT ALLOWED.
Answer: Maintain a prefix and suffix product array and calculate accordingly
Puzzle question: When a man goes to a temple, he gives half of the flowers he has to the gatekeeper and 100 flowers to the gods. In this manner, after visiting 3 temples, he’s left with 0 flowers. How many flowers did he have to begin with?&
Answer:
```
f(f(f(N))) = 0, find N where f(N) = N/2 - 100 
```

Technical Interview 2:

Explain heap and the various types of heaps
Which data structure is convenient for performing BFS
Answer: Queue.
What are the possible implementations of a queue and which one would you prefer?
Answer: Linked List and Array. I would prefer Linked List as array offers constant time random access which is not required. Array resizing would create overheads on insertions
I was given an SQL query involving two tables which had to solved using LEFT JOIN
Given an array of unique elements, design a function that will return a unique sequence of all its elements every time it is called&.
Answer: Start with sorted order. The desired function would be the nextPermutation() function.
Puzzle question: There is a book whose pages are numbered from 1-150. How many digits are used in enumerating all the pages?

Technical Interview 3:

What is the best and worst-case time complexity of quicksort?
For what type of input does the worst-case time complexity of quicksort occur?
Answer: For input array in ascending or descending order
Describe the phases of a compiler.
Generate all Parenthesis – II from. The problem is Print all combinations of balanced parentheses
Find the maximum subarray sum and also report the indices of the subarray

HR Round: This round was fairly straightforward. I was asked to talk about my technical interests, hobbies, and whether I was willing to relocate

Verdict: Selected for the role of Server Technology Engineer.

Tips:

Be calm and composed
Be thorough with your CS subjects
For puzzle questions, write down precise mathematical steps to make solving them easier
Speak eloquently in the HR round

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Walmart Interview Experience Aug-2020 (On-Campus)

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Walmart visited our campus in August 2020. The complete interview process was virtual. It was a 5 round process.

Round 1 (duration 90 minutes): The first round was unsupervised round on HackerEarth. It had 25 MCQ’s (25 marks) and 1 Coding question(25 marks).

MCQ’s: MCQ’s included Computer Network (CN), Operating System (OS), DBMS, and aptitude questions. MCQ’s were easy and medium level.
Coding Question: The coding question was a medium-difficult level question. This question was the decider for shortlisting (since MCQs were easy).
Question: Fake Palindrome: Return the number of Fake Palindrome substring in a string, where Fake Palindrome is a string whose anagram is a palindrome.

Test Case 1:

Input: ABAB 
Output:7    
Explanation: (“A”,”B”,”A”,”B”,”ABA”,”BAB”,”ABAB”)

Test Case 2:

Input: AAA 
Output: 6   
Explanation: (“A”,”A”,”A”,”AA”,”AA”,”AAA”)

Many students got partial marks for this question using a map for every substring. I had used bit masking concept for solving this question (Maybe overkill for this question, but it cleared all test cases)

23 students were selected for the next round.

Round 2 (duration 45-60 minutes): Second round was a technical round over Zoom Meetings. The interviewer asked about CN, OS, and DS/Algo.

Layers
Virtual Memory
Segmentation
Process and Threads
Kernel
Protocols (HTTP, TELNET, FTP)
VPN
Routing
Types of Binary Trees
JAVA (OOPS concept, Exceptions, etc.)
Coding Question (Greedy and Dynamic Programming question)

These were some questions he asked.

The coding question was very easy compared to the first round. He wanted to know the approach and intuition for every solution. There were some trick questions in the interview like given post-order, design a tree.

15 students were selected for the next round.

Round 3 (Duration 60 minutes): Third Round was a technical round over a Zoom Meeting. This was DS/Algo round. I was asked to code and execute questions on IDE.

Longest Increasing Subsequence.
Find a continuous subarray whose sum is equal to target sum. I solved the question with iterative approach(O(n^2)) and map approach(O(n)).
Iteratively find the postorder of a tree (stack approach).

12 students were shortlisted.

Round 4(Duration 30-45 minutes): Fourth Round was a Managerial round.

I was asked about my internship, what did I learn there, and what obstacles I faced during the internship.
Interviewer asked about the project. Also, asked some software engineering question like the Waterfall Model.
What is your approach to learning new technology?
Why do you want to join Walmart and how are you fit for the job?

These were some of the questions asked during my interview.

Round 5(Duration 20-30 minutes): Fifth Round was HR round.

Tell me about yourself.
What do you know about Walmart?
Are you interested in Higher Studies?
How do you adapt and overcome a difficult situation?
Your CGPA is relatively less, why so?
The Toughest Decision

These were some questions asked in the HR round.

10 students have shortlisted 5 students for Full -Time + Internship and 5 students for Internship(performance-based conversion to FTE).

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