$p="";我将其换成$p=null;同样通过。我想,这里的""和null应该都是一样的,赋值为空。
2016-07-31
echo $m1 = memory_get_usage();
echo "<br/>";
$str_string1 = '我是字符串';
echo $m2 = memory_get_usage()-$m1;
echo "<br />";
$str_string2 = "我是字符串";
echo $m3 = memory_get_usage()-$m1-$m2;
echo "<br />";
echo $str_string1;
echo "<br />";
echo $str_string2;
echo "<br/>";
$str_string1 = '我是字符串';
echo $m2 = memory_get_usage()-$m1;
echo "<br />";
$str_string2 = "我是字符串";
echo $m3 = memory_get_usage()-$m1-$m2;
echo "<br />";
echo $str_string1;
echo "<br />";
echo $str_string2;
2016-07-30
<?php
echo $m1 = memory_get_usage();
echo "<br/>";
$str_string1 = '我是字符串';
echo $m2 = memory_get_usage()-$m1;
echo "<br />";
$str_string2 = "我是字符串";
echo $m3 = memory_get_usage()-$m1-$m2;
echo "<br />";
echo $str_string1;
echo "<br />";
echo $str_string2;
?>
echo $m1 = memory_get_usage();
echo "<br/>";
$str_string1 = '我是字符串';
echo $m2 = memory_get_usage()-$m1;
echo "<br />";
$str_string2 = "我是字符串";
echo $m3 = memory_get_usage()-$m1-$m2;
echo "<br />";
echo $str_string1;
echo "<br />";
echo $str_string2;
?>
2016-07-30