PHP Make a simple if-isset-empty function -

i'm coding worksheet app printer company. i'm getting flood of forms. every single input field have check if $_post variables set, , if, echo value. (in case of error, example after validation error, user shouldn't retype whole form)

sample code:

if(isset($_post['time'])&&!empty($_post['time'])){echo $_post['time'];} 

i had implement hundred times. tried figure out kind of function make simple , readable.

something this:

function if_post_echo($key, $default = "") {     if(isset($_post[$key])&&!empty($_post[$key])){     echo $_post[$key];        }else{     echo $default;        } } 

but wont work. have tried pass in $_post $key variable this:

if_post_echo($_post['time'])  function if_request_echo($key, $default = "") {         if(isset($key)&&!empty($key)){         echo $key;            }else{         echo $default;            }     } 

and tried this:

function if_request_echo($key, $default = null) {     return isset($_request[$key])&&!empty($_request[$key]) ? $_request[$key] : $default; } 

without reasonable outcome.

the question:

how can forge function looks necessary $_post variable , returns or if unset returns empty string. , there way $_get , $_request, too? (or duplicate?)

your php testing function:

<?php function test_req($key, $default = '') {     if(isset($_request[$key]) ,        !empty($_request[$key])) {         return $_request[$key];     } else {         return $default;     } } ?> 

then in form html:

<input name="my_field" value="<?php echo htmlentities(test_req('my_field')); ?>" /> 

$_request (linked) php super global contains both post ($_post) , ($_get) request parameters.

if want capture post request parameters be:

<?php function test_req($key, $default = '') {     if(isset($_post[$key]) ,        !empty($_post[$key])) {         return $_post[$key];     } else {         return $default;     } } ?> 

for example.