// web development

What Is HTML?

HTML is the markup language used to describe the structure and meaning of content on web pages. It tells a web browser what elements exist on a page and how those elements relate to one another.

// definition

HTML means HyperText Markup Language

HTML stands for HyperText Markup Language.

It is the standard markup language used to structure content on the World Wide Web.

HTML can describe headings, paragraphs, links, images, lists, tables, forms and many other parts of a web page.

// example

What does HTML look like?

A very simple piece of HTML might look like this:

<h1>Freelance Coder</h1> <p>Welcome to my website.</p>

The browser interprets the first element as a main heading and the second as a paragraph.

// elements

HTML is built from elements

An HTML element usually consists of an opening tag, some content and a closing tag.

<p>This is a paragraph.</p>

<p>

The opening tag marks the beginning of the paragraph.

</p>

The closing tag marks the end of the paragraph.

// terminology

A tag and an element are not quite the same thing

People often use the words interchangeably, but there is a useful distinction.

<h2>About Me</h2>

<h2> is a tag.

The complete structure including the opening tag, content and closing tag is the HTML element.

// attributes

Elements can have attributes

Attributes provide additional information about an HTML element.

<a href="https://example.com">Visit Example</a>

The href attribute tells the browser where the link should go.

<img src="photo.jpg" alt="A photograph">

Here, src identifies the image file and alt provides alternative text.

// document

A complete HTML document has a structure

<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Freelance Coder</title> </head> <body> <h1>Hello, world!</h1> <p>This is my web page.</p> </body> </html>

// head

The <head> contains information about the page

The head normally contains metadata and resources used by the document rather than the main visible page content.

Page Title Character Encoding Metadata Stylesheets Scripts

// body

The <body> contains the page content

Most of the content that users see and interact with appears inside the body element.

<body> <h1>My Website</h1> <p>Welcome to my website.</p> <a href="/contact">Contact me</a> </body>

// common elements

Some common HTML elements

Element	Purpose
<h1>	Main heading
<p>	Paragraph
<a>	Link
<img>	Image
<ul>	Unordered list
<ol>	Ordered list
<table>	Tabular data
<form>	User input form

// hypertext

HTML links pages together

The "HyperText" part of HTML refers to the ability to connect documents through hyperlinks.

<a href="https://example.com">Open website</a>

Links are one of the fundamental ideas behind the web. They allow users to move between pages, websites and other resources.

// nesting

HTML elements can contain other elements

<article> <h2>What Is HTML?</h2> <p> HTML structures web content. </p> </article>

This creates a hierarchical document structure.

The article contains both a heading and a paragraph.

// semantic html

HTML can describe meaning, not just appearance

Modern HTML includes semantic elements that describe the purpose of different sections of a page.

<header> <nav> <main> <article> <section> <footer>

Semantic HTML can make documents easier for browsers, developers, search engines and assistive technologies to understand.

// html + css + javascript

HTML, CSS and JavaScript have different jobs

HTML

Defines the structure and meaning of the content.

CSS

Controls presentation, layout, colours, spacing and visual design.

JavaScript

Adds behaviour, logic and interactive functionality.

Together

These technologies form much of the foundation of modern front-end web development.

// structure vs style

HTML describes what something is

Consider:

<h1>Freelance Coder</h1>

HTML tells the browser that this text is the main heading.

CSS could then decide that the heading should be blue, large and centred.

h1 { color: blue; font-size: 42px; text-align: center; }

Keeping structure and presentation separate is an important principle of web development.

// markup language

HTML is a markup language

HTML is generally described as a markup language, rather than a programming language.

Its main purpose is to mark up and describe the structure and meaning of document content.

HTML structures content. It does not by itself provide the general-purpose programming logic associated with languages such as JavaScript, Python or PHP.

// utf-8

HTML and UTF-8

HTML is text, so character encoding matters.

Modern pages commonly declare UTF-8 using:

<meta charset="UTF-8">

This helps browsers correctly interpret characters such as:

£ € é π √ ≤ ≥ 日

// browser

The browser interprets the HTML

When a browser receives an HTML document, it parses the markup and constructs an internal representation of the page.

HTML file ↓ Browser parses HTML ↓ Document structure ↓ CSS applied ↓ JavaScript can interact with the page ↓ Rendered web page

The browser does not simply display the HTML source code. It interprets the markup and renders the corresponding document.

// accessibility

Good HTML also improves accessibility

Correctly structured HTML gives information about headings, navigation, images, forms and other content.

Assistive technologies such as screen readers can use this structure to help users understand and navigate a page.

<img src="chart.png" alt="Bar chart showing monthly sales" >

The alternative text describes the image when the image itself cannot be seen.

// uses

Where is HTML used?

Web Pages Blogs Web Applications Landing Pages Online Stores Documentation Forms Email Templates

// summary

The structure of the web.

HTML is the markup language used to describe the structure and meaning of web content. It uses elements, tags and attributes to define headings, paragraphs, links, images, forms and other parts of a document, providing the structural foundation on which CSS and JavaScript can build.

// data formats

What Is JSON?

JSON is a lightweight text-based format for representing structured data. It is widely used by websites, APIs, applications and programming languages to exchange information in a form that is relatively easy for both humans and computers to understand.

// definition

JSON means JavaScript Object Notation

JSON stands for JavaScript Object Notation.

It is a text-based format used to represent structured information using objects, arrays, names and values.

Although JSON originated from JavaScript syntax, it is now used independently by many programming languages and software systems.

// example

What does JSON look like?

Suppose we want to store information about a customer.

{ "name": "Alice Smith", "email": "alice@example.com", "orders": 4, "active": true }

This is a JSON object.

Each piece of information consists of a name and a value.

// name-value pairs

JSON uses name-value pairs

Consider this line:

"name": "Alice Smith"

The name of the property is:

"name"

and its value is:

"Alice Smith"

A colon separates the property name from its value. Commas separate different properties.

// objects

JSON objects use curly braces

An object begins with { and ends with }.

{ "product": "Keyboard", "price": 49.99, "stock": 12 }

Objects are useful when several named properties belong to the same thing.

// arrays

JSON arrays use square brackets

An array represents an ordered collection of values.

[ "HTML", "CSS", "JavaScript", "PHP" ]

Arrays begin with [ and end with ].

// collections

Arrays can contain objects

This is extremely common when working with APIs and databases.

[ { "name": "Alice", "orders": 4 }, { "name": "Ben", "orders": 7 }, { "name": "Carla", "orders": 2 } ]

Here, the array contains three separate customer objects.

// data types

JSON supports several kinds of values

Type	Example
String	"Freelance Coder"
Number	42
Boolean	true
Null	null
Object	{ "name": "Alice" }
Array	[1, 2, 3]

// strings

JSON strings use double quotation marks

{ "city": "London" }

JSON requires strings and property names to use double quotation marks.

Important: JSON does not allow property names or strings to be written using single quotation marks in standard JSON syntax.

// boolean values

JSON can represent true and false

{ "active": true, "verified": false }

Boolean values are written without quotation marks.

// null

JSON can represent no value

{ "middleName": null }

The value null represents the intentional absence of a value.

// nesting

JSON can represent complex structures

Objects can contain other objects and arrays.

{ "customer": { "name": "Alice", "location": { "city": "Birmingham", "country": "United Kingdom" }, "orders": [ { "id": 1001, "total": 49.99 }, { "id": 1002, "total": 25.50 } ] } }

This creates a hierarchical structure in which related information can be grouped together.

// APIs

JSON is widely used by APIs

One of JSON's most important uses is transferring data between software systems.

For example, an application might request information about a product from an API and receive:

{ "id": 1042, "name": "Wireless Keyboard", "price": 39.99, "available": true }

The application can then read the JSON and use the values in its own interface or processing.

// data exchange

JSON helps systems communicate

Website ↓ API request ↓ Server ↓ JSON response ↓ Website

JSON provides a common structure that both sides can understand.

// json vs csv

JSON and CSV solve different problems

CSV works particularly well for simple tabular data.

Name,Orders Alice,4 Ben,7

JSON can represent more complex nested structures.

{ "customers": [ { "name": "Alice", "orders": [ 1001, 1002 ] } ] }

CSV	JSON
Rows and columns	Objects and arrays
Excellent for tables	Excellent for structured data
Flat structure	Can be nested

// json vs xml

JSON and XML can represent similar data

This XML:

<customer> <name>Alice</name> <orders>4</orders> </customer>

could be represented in JSON as:

{ "customer": { "name": "Alice", "orders": 4 } }

JSON is often more compact for application data, while XML provides additional features that can be useful for document-oriented and specialised systems.

// plain text

JSON is a text format

JSON may represent complex information, but the underlying document is still text.

This means JSON can be opened in a text editor, transmitted over a network and processed by many different programming languages.

Text-Based Structured Portable Machine-Readable Human-Readable

// utf-8

JSON and UTF-8

JSON exchanged between systems is commonly encoded using UTF-8.

{ "name": "João", "currency": "£", "symbol": "π", "message": "Olá" }

UTF-8 allows JSON to represent a very wide range of Unicode characters reliably.

// .json files

JSON can be stored in .json files

JSON data saved as a standalone file normally uses the .json file extension.

customers.json products.json settings.json data.json

JSON does not have to exist as a separate file, however. It can also be sent directly between applications and APIs.

// advantages

Why is JSON so widely used?

Readable

Its structure is relatively easy for people to inspect and understand.

Lightweight

JSON can represent structured information without large amounts of additional markup.

Structured

Objects, arrays and nested values can represent sophisticated data structures.

Widely supported

Most modern programming languages and web technologies can read and generate JSON.

// uses

Where is JSON used?

APIs Web Applications Databases Configuration Automation AI Systems Data Exchange JavaScript Mobile Apps Cloud Services

// syntax

JSON syntax is strict

Valid JSON must follow specific rules.

Property names use double quotes.

Strings use double quotes.

Properties are separated by commas.

Trailing commas are not permitted in standard JSON.

For example, this is valid:

{ "name": "Alice", "age": 30 }

But this is not valid standard JSON:

{ 'name': 'Alice', 'age': 30, }

// summary

Simple text. Structured information.

JSON is a text-based format for representing structured data using objects, arrays and name-value pairs. Its simplicity, flexibility and widespread software support make it one of the most important formats for APIs, websites, applications, automation and modern data exchange.

// character encoding

What Is UTF-8?

UTF-8 is a character encoding used to represent text inside computers. It provides a way of turning Unicode characters such as letters, numbers, mathematical symbols and characters from many languages into bytes that a computer can store and process.

// definition

UTF-8 turns characters into bytes

UTF-8 stands for Unicode Transformation Format - 8-bit.

It is an encoding system that converts Unicode characters into sequences of bytes.

This allows text to be stored in files, transmitted across networks and interpreted consistently by different computer systems.

// why encoding?

Computers do not store letters directly

When we look at a computer screen, we see characters:

A £ π é 日 😀

But computer storage ultimately consists of binary data. The computer therefore needs a defined system for representing each character using numbers and bytes.

Character → Unicode code point → UTF-8 encoding → Bytes

// unicode

First, understand Unicode

Unicode is a standard that assigns characters unique numerical identifiers called code points.

A Unicode code point is normally written using U+ followed by hexadecimal digits.

Character	Unicode code point
A	U+0041
£	U+00A3
é	U+00E9
π	U+03C0
€	U+20AC
😀	U+1F600

// unicode vs utf-8

Unicode and UTF-8 are not the same thing

This distinction is important.

Unicode

Defines characters and assigns them code points.

UTF-8

Defines how those Unicode code points are encoded into bytes.

Unicode tells us that the pound sign is U+00A3. UTF-8 tells the computer which bytes should be used to represent that character.

// bytes

UTF-8 uses between one and four bytes

UTF-8 is a variable-length encoding.

Different characters require different numbers of bytes.

Character	UTF-8 bytes	Bytes used
A	41	1
£	C2 A3	2
π	CF 80	2
€	E2 82 AC	3
😀	F0 9F 98 80	4

Important: the hexadecimal byte values shown above are the UTF-8 encoding of each character, not the Unicode code point itself.

// ascii compatibility

UTF-8 is compatible with ASCII

One of the reasons UTF-8 became so successful is its compatibility with ASCII.

The first 128 Unicode characters use exactly the same single-byte values as ASCII.

A = U+0041 = UTF-8 byte 41 B = U+0042 = UTF-8 byte 42 1 = U+0031 = UTF-8 byte 31

This means ordinary English text using basic letters, digits and punctuation is very compact in UTF-8.

// multilingual text

UTF-8 can represent text from many languages

UTF-8 is not limited to English.

English: Hello Português: Olá Español: Información Français: Éducation Greek: π Japanese: 日本 Currency: £ € ¥ Mathematics: ≤ ≥ ± √ ∞ Emoji: 😀

All of these characters can exist within the same UTF-8 encoded document.

// encoding errors

What happens when the wrong encoding is used?

Text can become corrupted-looking when software interprets bytes using the wrong character encoding.

For example, a pound sign encoded as UTF-8 may sometimes incorrectly appear as:

Expected: £50 Incorrect interpretation: £50

This type of garbled text is often called mojibake.

The data may not actually be damaged. The same bytes may simply have been interpreted using the wrong encoding.

// txt files

UTF-8 and .txt files

A .txt file tells us that a file contains plain text, but it does not automatically tell us which character encoding was used.

.txt ≠ automatically UTF-8

A text file might use UTF-8, ASCII, Windows-1252 or another encoding.

For modern text files, UTF-8 is generally the most useful and interoperable choice.

// csv files

UTF-8 and CSV

CSV is also a text-based format, so character encoding matters.

Name,City,Amount João,Lisboa,£50 Élodie,Paris,€75 Sofia,Athens,€40

Saving this file using UTF-8 helps preserve accented characters and currency symbols when the file moves between compatible systems.

// xml

UTF-8 and XML

XML documents can explicitly declare their character encoding.

<?xml version="1.0" encoding="UTF-8"?>

This tells the software reading the document that its characters are encoded using UTF-8.

// html

UTF-8 on websites

Websites also need to specify how text should be interpreted.

Modern HTML pages commonly include:

<meta charset="UTF-8">

This tells the browser to interpret the document using UTF-8.

Correct encoding is important for displaying names, symbols, mathematical notation, international text and other characters reliably.

// advantages

Why is UTF-8 so widely used?

Unicode support

It can represent the full range of Unicode code points.

ASCII compatible

Basic ASCII characters retain their original one-byte representation.

Efficient

Common English characters require only one byte, while additional bytes are used when necessary.

Portable

UTF-8 is supported across operating systems, programming languages, databases and web technology.

// where it appears

UTF-8 appears throughout modern computing

UTF-8 can be used with many text-based technologies and file formats.

TXT CSV XML JSON HTML CSS JavaScript APIs Databases Web Pages

// key idea

The file format and the encoding are different things

This is one of the most useful concepts to understand.

File format: describes how information is organised.

Character encoding: describes how the characters themselves are represented as bytes.

CSV = structure of the data UTF-8 = encoding of the characters

A CSV file can therefore be encoded using UTF-8. An XML document can be encoded using UTF-8. A plain .txt file can also be encoded using UTF-8.

// summary

Characters become bytes.

UTF-8 is a character encoding that converts Unicode characters into sequences of one to four bytes. It allows computers to store and exchange text from many languages, symbols and writing systems while remaining compatible with ASCII.

// file formats

What Is XML?

XML is a text-based format for storing and exchanging structured information. It uses descriptive tags to show what each piece of data means and how different pieces of information relate to one another.

// definition

XML means Extensible Markup Language

XML stands for Extensible Markup Language.

It is a plain-text format designed to describe, organise, store and exchange structured information.

XML does this using tags that identify the meaning and structure of the data.

// example

What does XML look like?

Imagine that we want to store information about a customer.

<customer> <name>Alice Smith</name> <email>alice@example.com</email> <orders>4</orders> </customer>

The information is surrounded by tags such as <name>, <email> and <orders>.

These tags give meaning to the values rather than simply storing them in a fixed position.

// tags

Opening and closing tags

Most XML elements have an opening tag and a closing tag.

<name>Alice Smith</name>

Here:

<name>

This is the opening tag. It marks the beginning of the element.

</name>

This is the closing tag. The forward slash indicates the end of the element.

// structure

XML is hierarchical

One of XML's most important features is that elements can contain other elements.

This creates a tree-like hierarchy.

<shop> <customer> <name>Alice</name> <orders> <order> <id>1001</id> <total>49.99</total> </order> <order> <id>1002</id> <total>25.50</total> </order> </orders> </customer> </shop>

In this example, the shop contains a customer, the customer contains orders, and each order contains its own information.

// root element

An XML document needs a root element

A well-formed XML document has one outermost element that contains the rest of the document.

<customers> <customer> <name>Alice</name> </customer> <customer> <name>Ben</name> </customer> </customers>

Here, <customers> is the root element.

// attributes

XML elements can also have attributes

Attributes provide additional information about an element.

<customer id="1042" status="active"> <name>Alice Smith</name> </customer>

In this example:

id="1042" status="active"

These are attributes attached to the customer element.

// extensible

Why is XML called "extensible"?

XML does not give you a fixed set of tags.

Instead, you can create tags appropriate to the information you are describing.

<book> <title>Introduction to Data</title> <author>Jane Smith</author> </book>

A different system might use:

<product> <sku>ABC-100</sku> <price>29.99</price> </product>

The tags can therefore be designed around the type of information being stored.

// declaration

The XML declaration

XML documents may begin with a declaration such as:

<?xml version="1.0" encoding="UTF-8"?>

This tells software that the document uses XML version 1.0 and that the text is encoded using UTF-8.

Important: XML is a text format, so character encoding matters. UTF-8 is extremely common because it can represent characters from many languages and writing systems.

// escaping

Some characters need special handling

Because characters such as angle brackets are used as part of XML syntax, certain characters must be represented using special entity references when they are intended as data.

Character	XML representation
<	&lt;
>	&gt;
&	&amp;
"	&quot;
'	&apos;

// rules

XML has strict structural rules

XML must be well formed for an XML parser to process it correctly.

Tags must close

Elements normally need corresponding opening and closing tags.

Tags must nest correctly

Elements cannot overlap one another incorrectly.

One root element

The document must have one outermost root element.

XML is case-sensitive

<Name> and <name> are treated as different tags.

// nesting

Correct nesting matters

This is valid:

<customer> <name>Alice</name> </customer>

But this structure is invalid:

<customer> <name>Alice </customer> </name>

The elements have been closed in the wrong order.

// xml vs html

XML and HTML look similar, but they have different purposes

Both use angle-bracket tags, but they are designed for different jobs.

XML	HTML
Describes and structures data	Structures content for web pages
Custom tags can be created	Uses predefined HTML elements
Focused on information	Focused on webpage structure and presentation
Strict syntax	Browsers are often more forgiving

<!-- XML --> <product> <name>Keyboard</name> <price>49.99</price> </product> <!-- HTML --> <h1>Keyboard</h1> <p>Price: £49.99</p>

// xml vs json

XML and JSON can represent similar information

XML and JSON are both commonly used to represent structured data.

For example, this XML:

<customer> <name>Alice</name> <orders>4</orders> </customer>

could be represented in JSON as:

{ "customer": { "name": "Alice", "orders": 4 } }

JSON is often more compact, while XML offers features such as attributes, namespaces and document-oriented structures that can be useful in more complex systems.

// uses

What is XML used for?

XML has been used extensively for exchanging and storing structured information across many kinds of software.

Configuration Files Data Exchange Web Services Document Formats Product Feeds Sitemaps RSS Feeds APIs Data Imports Data Exports

// real-world example

Website sitemaps commonly use XML

A website can provide an XML sitemap containing information about its pages.

<urlset> <url> <loc>https://example.com/</loc> </url> <url> <loc>https://example.com/about</loc> </url> </urlset>

Search engines and other software can process this structured information automatically.

// data management

Why XML matters in data management

XML allows information to describe its own structure.

Instead of relying purely on column positions or an external explanation, tags can identify what individual pieces of information represent.

<employee> <name>Tiago</name> <department>Technology</department> <active>true</active> </employee>

This makes XML useful when information needs to move between systems while retaining a clear hierarchical structure.

// plain text

XML is still plain text

Although XML can represent complex structures, the file itself is text.

This means an XML file can be opened in a text editor, inspected by a person and processed by software.

Readable Portable Structured Machine-Readable Text-Based

// summary

Text with structure and meaning.

XML is a text-based language for representing structured information. It uses tags, elements, attributes and hierarchical relationships to describe what data means and how different pieces of information fit together.

// file formats

What Is a .csv File?

A .csv file is a simple way of storing tabular data as plain text. It is commonly used to move information between spreadsheets, databases, websites and software applications.

// definition

CSV means Comma-Separated Values

CSV stands for Comma-Separated Values.

A .csv file stores data as plain text, usually with each line representing a row and commas separating the individual values within that row.

This makes CSV particularly useful for information that naturally fits into rows and columns.

// example

What does CSV data look like?

Imagine a spreadsheet containing customer information:

Name,Email,Orders Alice,alice@example.com,4 Ben,ben@example.com,7 Carla,carla@example.com,2

The first line contains the column headings. Each line after that represents one record.

Name	Email	Orders
Alice	alice@example.com	4
Ben	ben@example.com	7
Carla	carla@example.com	2

The CSV file and the table contain essentially the same information. The difference is how that information is represented.

// structure

Rows, columns and values

Rows

Each line normally represents one record, such as one customer, one product or one transaction.

Columns

Each position within a row represents a particular field, such as a name, price or date.

Delimiter

Commas normally separate the fields from one another, giving the format its name.

Header row

Many CSV files begin with a row containing the names of the columns, although this is not compulsory.

// plain text

A CSV file is still a text file

CSV is a structured text format.

If you open a CSV file in a plain-text editor, you can normally read its contents directly.

However, spreadsheet software such as Microsoft Excel or Google Sheets can interpret the separators and display the information as rows and columns.

Plain Text Rows Columns Records Fields

// quoted values

What happens if the data itself contains a comma?

Sometimes a value needs to contain a comma of its own. In that situation, the value can be enclosed in double quotation marks.

Name,Location Alice,"Birmingham, England" Ben,"London, England"

The quotation marks tell software that the comma inside the location belongs to the value rather than separating two different columns.

// escaping

What about quotation marks inside a value?

If a quoted field itself contains a double quotation mark, CSV commonly represents it by doubling the quotation mark.

Product,Description Book,"The ""Advanced"" Edition"

This allows the quotation mark to remain part of the actual data.

// csv vs spreadsheet

A CSV file is not an Excel workbook

Excel can open CSV files, but that does not make CSV an Excel format.

A normal Excel workbook can store much more than simple tabular values. It can contain formatting, formulas, multiple worksheets, charts and other spreadsheet features.

Feature	CSV	Excel workbook
Rows and columns	Yes	Yes
Plain text	Yes	No
Multiple worksheets	No	Yes
Cell formatting	No	Yes
Charts	No	Yes

Important: when an Excel workbook is exported to CSV, features such as colours, fonts, charts and multiple worksheets are not preserved as part of the CSV format.

// why csv?

Why is CSV so widely used?

Simple

CSV has a straightforward structure that is relatively easy for both people and software to understand.

Portable

CSV files can move data between many different applications and operating systems.

Lightweight

There is very little additional information surrounding the actual data.

Programmable

Programming languages and data tools can easily read, create and transform CSV files.

// uses

What are CSV files used for?

CSV files are common anywhere structured data needs to move from one system to another.

Customer Data Product Lists Transactions Website Data Analytics Database Exports Affiliate Data Inventory Spreadsheets Data Migration

// encoding

CSV and UTF-8

Like other text files, a CSV file must use a character encoding.

UTF-8 is a particularly useful choice because it supports a huge range of characters and languages.

Name,City,Amount João,Lisboa,£25 Élodie,Paris,€40 Sofia,Athens,€32

Important: the .csv extension does not itself guarantee UTF-8. The character encoding is a separate property of the file.

// delimiters

Is a comma always used?

CSV literally means Comma-Separated Values, and commas are the standard delimiter associated with the format.

In practice, however, data files may also use other separators. For example, semicolons are sometimes used because of regional settings or software conventions.

Name;City;Orders Alice;Birmingham;4 Ben;London;7

Files using tabs as separators are commonly called TSV, meaning Tab-Separated Values.

// data management

Why CSV matters in data management

CSV is particularly useful because it provides a simple bridge between different systems.

A database can export records to CSV. A spreadsheet can open them. A script can transform them. Another application can then import the resulting file.

Database ↓ CSV ↓ Spreadsheet ↓ Script / Automation ↓ Another System

This makes CSV extremely useful for data migration, cleaning, imports, exports and automation.

// txt vs csv

How is CSV different from TXT?

Both .txt and .csv files can contain plain text.

The key difference is that CSV normally follows a tabular structure: values are separated into fields and records so that software can interpret them as rows and columns.

A general .txt file does not necessarily have that structure.

Format	Main purpose
.txt	General plain-text information
.csv	Structured tabular data

// summary

Simple text. Structured data.

A .csv file stores tabular information as plain text, normally using commas to separate values and new lines to separate records. Its simplicity makes CSV one of the most useful formats for exchanging data between spreadsheets, databases, websites and software systems.