Single quotation marks have stronger performance, but poor functionality
Double quotation marks can directly perform a simple analysis of the content of the string. For example, the performance of variables and special escape characters will be reduced accordingly
Generally use single quotes, if you reference a variable, consider using win-win numbers
Delimiter<<<name name; #
Single quotes cannot parse variables and escape characters, while double quotes and delimiters can parse variables and escape characters;
Did you want to write notes in the course, but ended up writing them in the Q&A ( Dog head)