Php-manual's Learning----"Language Reference"----"type"-----"string-string"

1. A string of strings consists of a series of characters, each of which is equal to one byte. This means that PHP can only support a 256 character set and therefore does not support Unicode.
2. String can reach 2GB maximum.
3. Syntax
A string can be expressed in 4 different ways:
? Single quotation marks
? Double quotes
? HEREDOC syntax structure
? NOWDOC syntax structure (since PHP 5.3.0)
4 single quotes are non-parsing variables, and double quotation marks can parse variables.

Php-manual's Learning----"Language Reference"----"type"-----"string-string"