<< in PHP

<< Available in PHP <运算符构建多行字符串序列的方法，通常称为here-document或表示为heredoc的简写。< p>

This method details the literal value of the string and preserves the underscore and other spaces (including indentation) of the string in the text. For example:

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         PHP2$author = ' Wixy '; 3 echo <<<_end4thisis a headline5 thisis the first line. 6 Thisis the second line. 7 $author. 8 _end; 9 ?>

The PHP parser outputs all the content in the middle of the two _end tags, which is equivalent to a string quoted in double quotes.

This means that we can write an entire HTML language directly into the PHP code, and then replace the specific dynamic parts with PHP variables.

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         PHP2$out =<<<_end3 ..... 4 _end; 5 ?>

You can also assign the contents of two tags to a variable in this way.

Note : The _end tag that is used to close must be placed on a single line, and no other content can be added to this line, even if comments or spaces are not allowed

The above describes the << in PHP<>

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