# Getting Started¶

## Using python shell¶

• Open terminal (ctrl+alt+t).
• Type:

$python  - If you have python 3 then type: $ python3

This will open python shell in your terminal.

>>>


Lets tryout a simple python code to print "Unlock the world of security", all you need is to use print function.

• open terminal and type:

$python3 >>> print("Unlock the world of security")  - In case of python 2 the above syntax will also work along with the following syntax : $ python
>>> print "Unlock the world of security"

The output will be displayed in the python shell as:
>>> Unlock the world of security


## Basic Data Types¶

• Integer eg: -4, 0, 32
• Float eg: -44.3, 0.55, 7.0
• Complex eg: 3+2i, 4-i, -2-3i
• Boolean true or false
• String eg: 'Smile', '44', 'disc0ver'

To check the datatype, python has built in function type().

>>> n=1729
>>>type(n)
<class 'int'>
>>>s="H4cker"
>>>type(s)
<class 'str'>
>>>f=17.29
>>>type(f)
<class 'float'>

Convertion to a valid datatype is possible with the help of typecasting.

>>>f=212.34
>>>int(f)
212
>>>num=33
>>>float(num)
33.0


## Strings¶

These are set of characters closed with double or single quotes.

string="security"

Here security is written in double quotes, hence is taken as a string.

With length as 8.

To check length, python has built-in funtion, len(string name).

>>> string="security"
>>>len(string)


Press enter.

Output

8

Index value starts from 0.

Things to know:

Syntax for extracting a part of the string :

string_name[starting:ending:incrementation]

>>>a='I can crack your password'
>>>len(a)


Output

25

It starts from 0 to 24, thus in total 25 characters.

>>>a[0:24]


Output

'I can crack your password'

For only the fisrt 5 characters.
>>>a[0:5]


Output

'I can'

For the 10th character.
>>>a[10]


Output

'k'

To Extract the characters at even indices.

To include the last character, we need to specify the ending point as 25.

>>>a[0:25:2]


Output

'Icncakyu asod'

Python has built-in funtion string_name.split("").

It will split the string into substrings when it encounters the character in quotations. If nothing is specifed in the quotes, then it will dispaly error.

Example 1

If we want to separate the string into subtrings, when there is a space:

>>>a.split(" ")

It will give us a list with the substrings which are separated by what is specified in quotations (here split(" ") i.e. space).

Output

['I', 'can', 'crack', 'your', 'password']

Example 2

>>>new='safe, secure, security'
>>>new.split(",")


Output

['safe', ' secure', ' security']