For a long time know print_r output when using a complex type, simply use echo, hereby today go into this question, what time to start with less direct echo, print, pinrt_f, nonsense
The first to write four types: plastic, strings, arrays, functions,
INTE $ = 2; // shaping $ STR = 'dwqdw'; // String $ ARR = [ '. 1', '2', '. 3']; // Array // function function XX () { echo 123 ; } echo $ not ; print ( $ not ); print_r ( $ not );
Results: 222, as output
var_dump ( echo $ not ); var_dump ( print ( $ not )); var_dump ( print_r ( $ not ));
Var_dump print using the three types of return,
Results: syntax error, unexpected 'echo' direct error o (╥﹏╥) o echo no return value, directly commented,
Summary: 2222int (1) 2bool (true) print returns 1, print_r returns true,
Start the next print string:
echo $str."<br>"; print($str)."<br>"; print_r($str)."<br>"; var_dump(echo $str)."<br>"; var_dump(print($str))."<br>"; var_dump(print_r($str))."<br>";
The results:. 1.var_dump (echo $ str) "<br>"; this is a direct error, echo-free return value, comment
2.dwqdw dwqdw dwqdwdwqdwint (1) dwqdwbool ( true), a normal printing print returns 1, print_r returns true
Print array:
echo $arr."<br>"; print($arr)."<br>"; print_r($arr)."<br>"; var_dump(echo $arr)."<br>"; var_dump(print($arr))."<br>"; var_dump(print_r($arr))."<br>";
The results:.. 1 var_dump (echo $ arr) "<br>"; this is a direct error, echo-free return value, comment
. 2.echo $ arr "<br>"; error; . Var_dump (echo $ arr) "<br>" ; error, Print ($ arr) "<br>";. Error var_dump (print ($ arr)) . "<br>"; error. Array to string conversion to convert the string array
Summary: pint echo not print array type
Print function type: lazy just say the results are only pinr_r other normal output can not print
Summary: 1.echo, print only print plastic, string type
2.print_r can print a variety of types (that white is the type will do)
3. echo return no value, print () Returns shaping 1, print_r () Boolean Returns true