print_r

(PHP 4 )

print_r -- Prints human-readable information about a variable

Description

bool print_r ( mixed expression)

print_r() displays information about a variable in a way that's readable by humans. If given a string, integer or float, the value itself will be printed. If given an array, values will be presented in a format that shows keys and elements. Similar notation is used for objects.

Remember that print_r() will move the array pointer to the end. Use reset() to bring it back to beginning.

提示: 任何直接把輸出到瀏覽器的結果,可使用輸出控制函數來擷取 此函數的輸出,在將之存入一個 字串(舉例說明)。

 pre 
 ?php
    $a = array ('a' =  'apple', 'b' =  'banana', 'c' =  array ('x','y','z'));
    print_r ($a);
? 
 /pre 


Which will output:

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


注: Prior to PHP 4.0.4, print_r() will continue forever if given an array or object that contains a direct or indirect reference to itself. An example is print_r($GLOBALS) because $GLOBALS is itself a global variable that contains a reference to itself.

See also ob_start(), var_dump(), and var_export().