> For the complete documentation index, see [llms.txt](https://python.microcisco.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://python.microcisco.com/python-inststitute-pcap/python-essentials-part-1/module-2/literals.md).

# Literals

Literals - The data in itself

## LITERALS

### A literal is data whose value is determined by the literal itself

{% hint style="info" %}
A good example might help :)

Take a look at the following set of digits' `123`

Its value is one hundred and twenty three!! Lets look at another option. What value is this? `c`
{% endhint %}

We can surmise its the speed of light or the lenght of a hypotenuse in Pythagaros' theorem. It can be anything and you cannot make a choice without further inofrmation!!\
And this is the clue: ***123 is a literal and c is not*** 

We use literals ***to encode data and put them into our code.***\
Let's see what conventions we have to obey!!

`print ("2")`\
`print (2)`\
`2`\
`2`

We can see one is a string ("2") and the other is an interger (2)\
They are stored in completely different ways inside the computers memory

* the string exists as just a string - a series of letters
* the integer is converted into bits
* the **`print ()`** function is able to show both in a human readable form

### Integers

Numbers handled by computers are of two types

* **Integers -** whole numbers, no fractional part.
* **floating-point** or (floats) are numbers that contain the fractional part

### Octals and Hexadecimal Numbers

We can write numbers in an octal (Base 8)  representation. If a number is preceded with a zero-oh (`0o`) it will be treated as an octal value. This means that the number must contain digits from the \[0...7] range only.\
We can also write numbers in a hexadecimal (Base16) representation\
 `0o123`  is an **octal** number with a decimal value of **`83`**\
 **`0x123`** is a hexadecimal number with a decimal value of **`291`**

### Floats - Non empty decimal fraction :)

 **Floats** are used in Python to represent numbers that **aren't integers** (whole numbers).\
Some examples of numbers that are represented as floats are 0.5 and -7.8237591.\
They can be created directly by entering a number with a decimal point, or by using operations such as division on integers.

* With floats we use the point instead of a comma to indicate the decimal remainder
* You can omit zero when it is the only digit in front or after the decimal point
  * `04` can be written as `.4`
* Computers can't store floats perfectly accurately, in the same way that we can't write down the complete decimal expansion of 1/3 (0.3333333333333333...). Keep this in mind, because it often leads to infuriating bugs!

### Floats vs Integers

Look at the following and there is a difference between the 2

* 4.0 is a **`floating-point`** number
* 4 is an **`integer`** 

For floating points its not only a point that indicates the number is a floating point but also the letter **`e`** used in scientific notation.\
For example speed of light is 300 000Km/s or 300 000 000 m/s which can be written as `3x10^8 m/s` or in Python its written as `3E8` (the letter E can also be used as a lower case `e` )

* The **exponent** has to be an integer
* The **base** *may* be an integer

A **float** can be ***added to an integer, because Python silently converts the integer to a float.***

### Coding Floats

Lets take Planck's Constant which is 6.62607 x 10^ -34. In python it will be written as **6.63607E-34**

Lets say we have decided to use the float literal `0.00000000000000000000001`\
**`print (0.00000000000000000000001)`**\
**`1e-21`**

{% hint style="danger" %}
As you saw previously, **dividing any two integers** produces a **float**.\
A float is also produced by **running an operation on two floats, or on a float and an integer**.
{% endhint %}

`print( 8 / 2 )       Ans=4.0`\
`print( 6 * 7.0 )     Ans=42.0`\
`print( 4 + 1.65 )    Ans=5.65`

### Using Quotes Inside Strings

When creating strings we surround them with quotes. Can either be single or double quotes.

**`>>>print ("Program 'Game Over' 2.0") Program`** \
**`Program 'Game Over' 2.0`**

The double quotes above are like bookends. They tell the computer where the string starts and ends, so you can use as many single quotes you want between the "bookends"\
This would be the same if the bookends were single quotes, you can use as many double quotes between the single quote bookends as you want.

**`>>>print ('Program "Game Over" 2.0')`**\
**`Program "Game Over" 2.0`**

`print ("I'm Monty Python")` \
`print ('I\'m Monty Python')`

`I'm Monty Python`\
`I'm Monty Python`

### Boolean Values

To conclude with Pythion Literals, there are 2 more and represent **'truthfulness'** \
Each time you ask Python if one number is greater than another, the questions results in the creation of some specific data - a **Boolean** value

This makes use of two values (and are case-sensitive) **'True'** or **'False'** denoted as `1` and `0`

## LAB

![](https://3018064759-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LudO0LP3BbNbyBiBB3l%2F-MGLSCydrA6Uq3iPt4Xp%2F-MGN58LJ3dElr0nNLjRV%2Fimage.png?alt=media\&token=2a810228-4f22-4b39-8274-fcf5ce83fd1c)

`print('"I\'m\"\n' '""learning""\n' '"""Python"""')`