Basics
Basics
Variables in PHP are represented by a dollar sign followed by the name of the variable. The variable name is case-sensitive.
Variable names follow the same rules as other labels in PHP. A valid variable name starts with a letter or underscore, followed by any number of letters, numbers, or underscores. As a regular expression, it would be expressed thus: '[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*'
Note: For our purposes here, a letter is a-z, A-Z, and the bytes from 127 through 255 (0x7f-0xff).
Note: $this is a special variable that can't be assigned.
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