Regular Expressions (RegEx):
============================
==> denoted as "RegEx".
==> is a sequence of characters that uses a search pattern to find a string or set of string.
==> RegEx ==> built-in module named as "re"
	module ==> a collection of files, classes, functions etc.
==> while using the RegEx, we must import this module.
Syntax:
	import re

import re

s = "Python Fullstack at Ashok IT"

m = re.search(r'at',s)
m1 = re.search('Fullstack',s)

print("The Start Index = ",m.start()) # 17
print("The End Index = ",m.end()) # 18

# range(start,end) ==> range() start to generate value from given "start" value and end with "end" value - 1

print("The Start Index = ",m1.start()) # 17
print("The End Index = ",m1.end()) # 18

===============================================
Meta Characters:
================
\
===

import re

s = "Ashok.IT"

m1 = re.search(r'.',s)

print(m1)

m1 = re.search(r'\.',s)

print(m1)
=================================
[]
==

ex: [abc]==> set of characters
[0,7] ==> range
[a-d] ==> range of alphabets ==> [abcd]

import re

s = "The Cat Sat on a wall."

p = "[b-r]" # bcdefghijklmnopqr
p1 = "[bde]"

result = re.findall(p,s)
r1 = re.findall(p1,s)

print(result)
print(r1)
===============================
^
===

import re

p = r'^The'

s = ['The quich brown box','The lazy dog','A quick brown fox']

for i in s:
    if re.match(p,i):
        print(i)
    else:
        print("Not found")

=================================
.
===
a.b

"python"
s = "p.t" ==> pyt

import re

s = "The quick brown fox jumps over the lazy dog"

p = r"brown.fox"
p1 = r"b.o"

m = re.search(p,s)

if m:
    print("Match Found")
else:
    print("No Match found.")

print(m)

m1 = re.search(p1,s)

print(m1)
====================
?
===
ex: ab?c

import re

s = "The quick brown fox jumps over the lazy dog"

p = r"b?o"

m = re.search(p,s)

print(m)