The difference between three kinds of output statements in php

The difference between three output statements of php

(1) echo is a PHP statement with no return value and is used to output an or Multiple strings

(2) print() is a function that can have a return value and can only print out the values ​​of simple type variables, such as int, string

(3) print_r() is a function that can have a return value and can print the value of complex type variables, such as arrays and objects

print_r detailed explanation: (Recommended learning: PHP programming from entry to proficiency)

bool print_r (mixed expression [, bool return])

The parameter return is in PHP 4.3.0 Added

If you want to capture the output of print_r(), you can use the return parameter. If this parameter is set to TRUE, print_r() will not print the results (this is the default action), but will return its output.

eg.

<?php
    $a = array (&#39;a&#39; => &#39;apple&#39;, &#39;b&#39; => &#39;banana&#39;, &#39;c&#39; => array (&#39;x&#39;,&#39;y&#39;,&#39;z&#39;));
    print_r ($a);
?>
<?php
    $a = array (&#39;a&#39; => &#39;apple&#39;, &#39;b&#39; => &#39;banana&#39;, &#39;c&#39; => array (&#39;x&#39;,&#39;y&#39;,&#39;z&#39;));
    $results = print_r ($a, true);//$results 包含了 print_r 的输出结果
    print_r ($results);
?>

The results of the above two methods are:

Array
(
    [a] => apple
    [b] => banana
    [c] => Array
        (
            [0] => x
            [1] => y
            [2] => z
        )
)

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