I'm confused about the term Ordinal value of a character or a string in php documentation. Can somebody tell me what exactly an ordinal value is?
One "character" in PHP is one byte. Note that this is misleading for multi-byte characters, in which one character (say "漢") is encoded in multiple bytes. Anyway though, a byte is 8 bits and can represent a number between 0 and 255. The ordinal value of a character byte is simply this numerical value.
ord('a') -> 97
Read http://kunststube.net/encoding if you need more background information about bytes/characters/encodings.
The Ordinal Value of a character is nothing but the numeric location of a character.
Ordinal value is Nothing but the ASCII value of a character And as we know every character takes one byte i.e. 8 bits and every bit can have either 0 or 1 as the possible value so every bit can have 2 values thus 8 positions can have power(2,8) = 256 combinations and every combination resembles 1 character like
00000000 => Null(0)
00010000 => Space(32)
(65 - 91) in Ascii => a-z
(97 - 122) in Ascii => (A-Z)
and (48 - 57) in Ascii => (0 - 9)
other combinations are assigned to other special chacater.
PHP have an inbuilt Function ord('a') which takes character as an argument and returns its ascii value i.e. 65 in this case