String Manipulations:
=====================
Java Strings Vs Python Strings:
===============================
In java:
=======
	equals():
	========
		s1.equals(s2) ==> compare the string's internal content 
	==
	===
		s1 == s2 ==> to compare the address of two strings
	
	contains()
	==========
		s1.contains("sub-string")


In python:
=========
	for string internal content validation ==> "== operator"
		s1 == s2
	for validating the addresses of two stings:
		identity operators (is/is not)
		s1 is s2
	for membership check: Membership operators (in/not in)
		'sub' in s1

# Identity operators and Membership operators

s1 = "python"
s2 = "python"
s3 = "Python"

print(id(s1))
print(id(s2))
print(id(s3))
print(s1 is s2)
print(s1 is s3)

print('P' in s3)

print(s1 == s2)

=================================================
-> Python strings allows the duplicated characters.
"level"

count():
========
-> can use to count the number of occurrences of the specified character/sub-string within the given main string.
Syntax:
	string-name.count('sub-string')
-> count() can also return '0' when the given sub-string is not present in the main string.
-> count() can also use to find the number of occurrences of the sub-string from the specified range of the main string.
Syntax:
	string-name.count('substring', start, stop)

s1 = "level"
s2 = "Python is Object Oriented Programming Language"

print(s1)
print("The Number of occurrences for letter 'l' is = ",s1.count('l'))
print("The Number of occurrences for letter 'e' is = ",s1.count('e'))
print("The Number of occurrences for letter 'v' is = ",s1.count('v'))
print("The Number of occurrences for letter 'a' is = ",s1.count('a'))

print("The Number of occurrences for letter 'e' is = ",s2.count('e',10,25))
print("The Number of occurrences for letter 'e' is = ",s2.count('e',s2.find('O'),s2.find('d')))
a = s2.find('O')
b = s2.find('d')
print("The Number of occurrences for letter 'e' is = ",s2.count('e',a,b))

=============================================================
replace():
==========
-> can use to replace the old-substring with new-substring.
Syntax:
	string-name.replace('old-substring', 'new-substring')

s = "Python is Difficult programming langauge"

print(s)

s = s.replace('Difficult','Easy')
print(s)
=========================================
Q: Is it possible to convert a string into List data?
======================================================
Ans: Yes

split():
========
-> we can convert the main string into list data.
Syntax:
	list-data-name = string-name.split('separator')

# string to list conversion

s1 = "Python is Easy"
s2 = "ravi.vrao.infs@gmail.com"
s3 = "29-01-2025"
s4 = "s9/01/2025"
s5 = "123aa345aa567aa789"

l1 = s1.split()
l2 = s1.split(' ')
l3 = s2.split('.')
l4 = s3.split('-')
l5 = s4.split('/')
l6 = s5.split('aa')

print(l1)
print(l2)
print(l3)
print(l4)
print(l5)
print(l6)

Q: Is it possible to convert a collection of strings into main string?
======================================================================
Ans: Yes

('29','01','2025')
['Ashok IT','Welcomes', 'You']

join()
======
=> based on the specified separator, the collection of strings can join into one main string.
Syntax:
	'separator'.join(collection of strings)

c1 = ('29','01','2025')
c2 = ['Ashok',"IT","Welcomes","You"]

s1 = ''.join(c1)
s2 = ' '.join(c1)
s3 = '-'.join(c1)
s4 = ' '.join(c2)

print(s1)
print(s2)
print(s3)
print(s4)

==============================================
case change:
============
# case change

s1 = "python".upper()
s2 = "PYTHON".lower()
s3 = "PyThOn pRoGrAmS".swapcase()
s4 = "python programming langauge".title() # titlce case
s5 = "python programming language".capitalize()

print(s1)
print(s2)
print(s3)
print(s4)
print(s5)
=================================================
String validation:
==================
startswith()
endswith()
isdigit()
isalnum()
isalpha()
islower()
isupper()
istitle()

# String validations
# mail id validation

mail = "ravivraoinfs@gmail.com"
url = "https://www.ashokit.in"
username = "ArjunKumar"

# if mail.endswith("@gmail.com"):
#     print("The enetered mail id is valid.")
# else:
#     print("The entered mail id is invalid.")

if url.startswith("https://"):
    print("The Given URL is valid.")
else:
    print("The given URL is invalid.")

print(username.isalpha())