STRING OPERATIONS
==================
REMOVAL OF SPACES FROM THE GIVEN STRING
==========================================
"""
strings ==> collection of characters
which enclosed with single quotes or double quotes.
characters ==> alphabets (upper case/lower case), digits (0 to 9) and special characters includes space

Note:
====
    when the string contains the space in between the string
        ex: "python programming" ==> the removal of the spa ce is no possible.
    when the string contains the spaces in left (at the beginning) or in right (at the end)
        ex: "   Python", "Python   ", "   python   " ==> spaces are considered to remove.

==> to remove the spaces from the string:
    three inbuilt methods:
        1) strip()
        2) lstrip()
        3) rstrip()
1) strip()
==========
Syntax:
    string_object.strip()
    ==> strip(), can allow to remove the spaces of the string in both left side spaces and in right spaces also.

2) lstrip()
==========
Syntax:
    string_object.lstrip()
    ==> lstrip() can remove the spaces from the left side of the string only.

3) rstrip()
==========
Syntax:
    string_object.rstrip()
    ==> rstrip() can remove the spaces from right part of the string only.
"""

s1 = "Python Programming"
s2 = "   Python"
s3 = "Python   "
s4 = "   Python   "

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

r1 = s1.strip()
r2 = s2.strip()
r3 = s3.strip()
r4 = s4.strip()

print(r1)
print(r2)
print(r3)
print(r4)
print()

r11 = s2.lstrip()
r12 = s3.lstrip()
r13 = s4.lstrip()

print(r11)
print(r12)
print(r13)
print()

r21 = s2.rstrip()
r22 = s3.rstrip()
r23 = s4.rstrip()

print(r21)
print(r22)
print(r23)
==================================

FINDING OF SUB-STRINGS
======================
==> POSSIBLE IN TWO APPROACHES:
	1) FORWARD DIRECTION (LEFT TO RIGHT)
	2) REVERSE DIRECTION (RIGHT TO LEFT)

1) FORWARD DIRECTION (LEFT TO RIGHT)
====================================
find()
====
Syntax:
	string_object.find('Sub-string')

str1 = "High Level Programming Language"

# when the given sub-string is at multiple places
# the first index of the given sub-string can return (The first Occurrence of the specified sub-string)

print(str1.find('i'))
print(str1.find('a'))

# when the sub-string is not present in the given string
# find() can return '-1'

print(str1.find('z'))

# if the sub-string with more than one character

print(str1.find('Level'))
print(str1.find("level"))

# find() can use to find the sub-string within the specified range also
# str_data.find(sub-string,start, end)
print(str1.find('L',1,15))

=======================================================

index()
======
Syntax:
	str_data.index('sub-string')

s1 = "Python Programming Language"

print(s1.index('P'))

# index() can always return the first occurrence of the given sub-string

# print(s1.index('b'))

# index() can return "value error", when the sub-string is not present in the given string.

print(s1.index('a',5,20))


===================================

find() Vs index()
============
find() can return: '-1' 
	when the sub-string is not present in the given string
index() can return "value error"
	when the sub-string is not present in the given string.

=======================================================

2) REVERSE DIRECTION (RIGHT TO LEFT)
===================================
rfind()
rindex()

s1 = "general purpose programming language"

print(s1.rfind('p'))
print(s1.rfind('P'))
print(s1.rfind('p',5,15))
print()

print(s1.rindex('p'))
# print(s1.rindex('P'))
print(s1.rindex('p',5,15))

===============================================

COUNTING OF NUMBER OF OCCURRENCES OF THE GIVEN SUB-STRING IN THE GIVEN STRING
===============================================================================
"ababcd"
"a" ==> 2
"b" ==> 2

count()
======
Syntax:
	str_data.count('sub-string')

s1 = ("Python Programming Language")

# if the sub-string at multiple place

print(s1.count('g'))
print(s1.count('m'))

# if the sub-string is not present
# return: '0'

print(s1.count('p'))

print(s1.count('r',5,15))

==========================================

Assignment:
==========
1) WAP IN PYTHON TO DISPLAY ALL POSITIONS OF SUB-STRING IN A GIVEN STRING.

MAIN STRING = "PYTHON PROGRAMMING LANGUAGE"
SUB STRING = 'P'

EXP_OUTPUT:
============
THE CHARACTER 'P' IS AT INDEX : 0
THE CHARACTER 'P' IS AT INDEX : 7