Single quotes, double quotes, and Heredoc initialize the difference between PHP strings

The string in PHP refers to the sequence of characters, which can be initialized in three ways: single quotes, double quotes, and use of Here Document (Heredoc).

One: when single quotation marks

①: Special characters that need to be escaped: backslashes and single quotes.

②: Because PHP does not check for insert variables and any escape sequences in single-quote strings, the single-quote string is intuitive and fast.

Common escape sequences:

Two: double quotes

①: Single quotes that recognize double-quoted strings and do not need to be escaped

②: Ability to identify inserted faces and escape sequences in a table

Single quotes, double quotes, and Heredoc initialize the difference between PHP strings