DEV Community: Kumar Shubham

Git Introduction.

Kumar Shubham — Sat, 12 Dec 2020 09:13:33 +0000

If you are into the programming world, you might have heard about git. Its complicated terms easily overwhelm the newcomers, this post is for those newcomers. Let’s start.

Why Git?

When we are working in a team, code sharing is always a problem, we don’t know who implemented what features and whose changes break the code. Here, Git comes as a savior.

What is Git?

Git is a distributed version control system(VCS). It is not the only Version Control System But the most famous one.
Git allows us to see changes made to code in past and also who made it. If there are any problems with the code then we can revert to an earlier version of our code too. Isn’t it great?? We can also upload our code to site like Github and Gitbasket. Our team members can clone or fork it from there and start to work simultaneously by creating a new branch.

Clone, fork, and branch might be led you to think that git is complicated but trust me it is not that complicated. Once you start learning step by step all will become clear.

In this blog, I’m going to teach you some basics git commands, enough to get you started. But first, install Git in your system.

Installation.

To download and install git in your system, click here and choose Git version for your OS and then follow the required installation steps.

After installing git you are ready to run git in your system.

Most Used Git Command.

git init
This command will make your repository(just a fancy name for folder) into a git repository.
git status
This command will show the status of your git repository like whether the files are tracked, staged, or not.
git add .
This command will stage all unchanged files.
git commit -m "message"
This command will commit your staged files and a version of your program is created. In the future, you can always revert to this version of your code(more on that later).
Replace the message with a meaningful text. It should be small and descriptive. Some common convention of writing commit messages are--

   * feat - a new feature
   * fix - a bug fix
   * docs - changes in documentation
   * style - everything related to styling
   * refactor - code changes that neither fixes a bug or adds a feature
   * test - everything related to testing
   * chore - updating build tasks, package manager configs, etc.

5 . git add < filename >
To stage, any particular file run this command and then run the commit command.

6 . git log
This command allows us to view information about the previous commit.

Chapter 1 : Values and Their Operators in Javascript

Kumar Shubham — Fri, 04 Dec 2020 07:03:23 +0000

Values

If you are familiar with any programming language, then you must have heard about values and values in JS are more or less similar.
Values are nothing just types of data that can be stored in system.

Types of Values

1.Number

Values of the number type are numeric value. In a JS program they are written as :
91,23.5

For very big number scientific notation is also used, like 3.997e8 which is equal to 3.997 * 10^8

Now we know how the numbers are stored in system but these are of no use if we can't perform any meaningful operation on them.
One of most important operation is Arithmetic Operation.
In Arithmetic Operation, we perform simple Multiplication or addition and a new value is produced from them.
E.g- 10+4*3
Here an arithmetic operation is performed on numbers. + and * are operators.

Special Numbers

There are 3 values in JS that is considered to be Special Numbers

Infinity
-Infinity
NaN

Infinity and -Infinity are respectively greatest positive and negative number possible. NaN stands for Not a Number. When we perform any numerical operation on data that does not yield any meaningful result it will give NaN. For example- 0/0 yield NaN.

2.Strings

Strings are used to store text. Text must be enclosed in quotes.

'I am string'
"I am String"
`I am String`

Two strings can be concatenated using +

'I'+ 'am' + 'String'

3.Boolean Values

Boolean values are just true and false.
If we check some condition and it's true the it return true otherwise false.

console.log(5>6)
// false
console.log(5<6)
// true

Don't worry about console.log , this is nothing just a way to see output. More on that later in other in next blogs.

<,>,=,<=,>= are Comparison Operators and have same functionality as in Mathematics.
!= is also an Conditional operator and it is used as not equal to. if we write a!=b, this means a is not equal to b.

Logical Operators are operators that can be performed on boolean types. They are AND,OR and NOT.
AND is binary operator(need two value to perform operation) written as && and it yield true iff both values given to it are true.

console.log(true && true)
// true
console.log(true && false)
//false

OR is also binary operator written as || and it yield true if at least any one of two given values are true.

console.log(true || true)
// true
console.log(true && false)
//true

NOT is a unary operator written as ! and it reverse the boolean value.

console.log(!true)
// true
console.log(!false)
//true

4.Empty Values

There are 2 Empty Values null and undefined. These two are personally value but does not have any value assigned to it.
They are used to denote the absent of meaningful data.
null is an assigned value but it means nothing.
*undefined * means a variable is declared but not defined yet.

If you feel uncomfortable understanding null and undefined, give it some time. As you know more about JS, it will become clear.

This blog is part of reading and writing blog for each chapter of eloquent Javascript book challenge, started by Tanay Sir. Follow him for more great contents.

Blog Post of 2nd chapter is coming soon.

Introduction To Regular Expression

Kumar Shubham — Tue, 30 Jun 2020 14:47:49 +0000

Commonly known as RegEx
RegEx is a string containing some special characters. These characters taken together forms a pattern.
This RegEx is used to check whether that particular pattern exists in any given string or not.

Python module re is imported to use Regular Expression methods

RegEx Functions

1.findall

It returns a list containing all matches or an empty list in case of no match.
It takes two parameter i.e, RegEx and String respectively.

2.Search

It Search the string for one match.
In case of match, it returns a MATCH OBJECT of only first match.
In Case of no match, it returns None.
It takes two parameter i.e,RegEx and String respectively.

3.Split

It returns a list where the string has been split at each match.
It takes 2-3 parameters.
First two parameters are RegEx and String respectively.
The Third parameter is an optional parameter,known as maxsplit parameter and takes int value as input.
This max split parameter controls maximum number of split can be performed on the String.

4.Sub

It looks for a match then replace it with new text string.
It takes 3-4 parameters,4th parameter is optional.
First 3 parameters are RegEx, newText and string respectively.
Fourth parameter is known as count parameter and takes int value as input.
This count parameter controls the maximum number of replacement performed on the string.