PHP - 如果条件，“更多零”

Question

Often in php i see code lines like

if(count($arr)) // $arr not empty

or

if(!$var) // $var is 0

But for me more informative is style like

if(count($arr) > 0) // or if(!empty($arr))

or

if($var == 0)

Which do same checking. What option is more correct? It's not a problem, but just code-style question. Maybe exists some standard(like PSR-2) for conditions like these.

Answer 1

The first statement is for counting as it says count(). This can be array values for example.

<?php
$array = array("x", "x", "x");
# Output: 3
echo count($array);
?>

The second statement is for checking if the variable $var is true or not. You can translate this line as if $var is not true, then..

<?php
$array = array("x", "x", "x");
if(!$array) {
    echo "True";

}else{

    echo "Does nothing..";
}
?>

The third statement is for checking if the counting for $var is greater than zero.

<?php
# Output: "Is not empty!"
$array = array("x", "x", "x");
if(count($array) > 0)
    echo "Is not empty!";

}else{

    echo "Empty..";
}
?>

And the last one is for checking if $var is equal to zero.

<?php
# Output: "Does nothing.."
$array = array("x", "x", "x");
if($array == 0) {
    echo "Is not empty!";

}else{

    echo "Does nothing..";
}
?>

So basically all these four statements have different meanings. As answer to your question would if(count($arr) > 0) be the best solution to check if the array has more then zero entries.