string manipulation
String manipulations:
charAt(indexNumber): it returns the char at the given index
length(): returns the total number of characters as int
length is ALWAYS one unit above the maximum index number
maxIndex: length()-1;
concat(Value): Concatenation, concats the given value to the String and returns a new value
toLowerCase(): converts to lowercase and returns a new String
toUpperCase(): converts to uppercase and returns a new String
trim(): removes the unused spaces , and returns new String
substring(beginning index, ending index):
creates substring of the string value from the beginning index till the ending
substring(beginning index):
creates substring of the string value from the beginning index till the end of the stringreplace(old Value, new Value): new value will be replaced with ALL the given old value, and returns new string
replaceFirs(old Value, new Value):
new value will be replaced with the very first given old value, and returns new string
indexOf(Value):
returns the index number of the first occurred character as an int
indexOf(Value): returns the index number of first occurred character, as int
lastIndexOf(Value): return the index number of last occurred character, as int
isEmpty(): identifies if the string is empty
true ==> string is empty,
false ==> String is not empty
equals(str): checks if two string' visible texts are equal or not
cares about the case sensitivity
A == a ==> false
equalsIgnoreCase(str): checks if two string' visible texts are equal or not
does not care case sensitivity
A == a ==> true
contains(str): checks if the str is contained in the string. returns boolean
if str is conatined ==> true
otherwise ==> false
startsWith(str): checks if the string starts with the given str. returns boolean
if starts with str ==> true
otherwise ==> false
endsWith(str): checks if the string ended with the given str. returns boolean
if ended with str ==> true
otherwise ==> false
