我运行了文章末尾包含的基准测试。比较方法:

Count ($arr) == 0:计数 Empty ($arr):空 $arr == []: comp (bool) $arr:类型转换

得到了以下结果

Contents  \method |    count     |    empty     |     comp     |     cast     |
------------------|--------------|--------------|--------------|--------------|
            Empty |/* 1.213138 */|/* 1.070011 */|/* 1.628529 */|   1.051795   |
          Uniform |/* 1.206680 */|   1.047339   |/* 1.498836 */|/* 1.052737 */|
          Integer |/* 1.209668 */|/* 1.079858 */|/* 1.486134 */|   1.051138   |
           String |/* 1.242137 */|   1.049148   |/* 1.630259 */|/* 1.056610 */|
            Mixed |/* 1.229072 */|/* 1.068569 */|/* 1.473339 */|   1.064111   |
      Associative |/* 1.206311 */|   1.053642   |/* 1.480637 */|/* 1.137740 */|
------------------|--------------|--------------|--------------|--------------|
            Total |/* 7.307005 */|   6.368568   |/* 9.197733 */|/* 6.414131 */|

empty和强制转换为布尔类型的区别是没有意义的。我已经多次运行这个测试，它们看起来基本上是相同的。数组的内容似乎没有发挥重要作用。这两者产生了相反的结果，但逻辑上的否定几乎不足以推动施法在大多数情况下获胜，所以我个人更喜欢空，因为在任何一种情况下都是易读的。

#!/usr/bin/php
<?php

//    012345678
$nt = 90000000;

$arr0 = [];
$arr1 = [];
$arr2 = [];
$arr3 = [];
$arr4 = [];
$arr5 = [];

for ($i = 0; $i < 500000; $i++) {
    $arr1[] = 0;
    $arr2[] = $i;
    $arr3[] = md5($i);
    $arr4[] = $i % 2 ? $i : md5($i);
    $arr5[md5($i)] = $i;
}

$t00 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
    count($arr0) == 0;
}
$t01 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
    empty($arr0);
}
$t02 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
    $arr0 == [];
}
$t03 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
    (bool) $arr0;
}
$t04 = microtime(true);

$t10 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
    count($arr1) == 0;
}
$t11 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
    empty($arr1);
}
$t12 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
    $arr1 == [];
}
$t13 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
    (bool) $arr1;
}
$t14 = microtime(true);

/* ------------------------------ */

$t20 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
    count($arr2) == 0;
}
$t21 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
    empty($arr2);
}
$t22 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
    $arr2 == [];
}
$t23 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
    (bool) $arr2;
}
$t24 = microtime(true);

/* ------------------------------ */

$t30 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
    count($arr3) == 0;
}
$t31 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
    empty($arr3);
}
$t32 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
    $arr3 == [];
}
$t33 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
    (bool) $arr3;
}
$t34 = microtime(true);

/* ------------------------------ */

$t40 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
    count($arr4) == 0;
}
$t41 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
    empty($arr4);
}
$t42 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
    $arr4 == [];
}
$t43 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
    (bool) $arr4;
}
$t44 = microtime(true);

/* ----------------------------------- */

$t50 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
    count($arr5) == 0;
}
$t51 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
    empty($arr5);
}
$t52 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
    $arr5 == [];
}
$t53 = microtime(true);
for ($i = 0; $i < $nt; $i++) {
    (bool) $arr5;
}
$t54 = microtime(true);

/* ----------------------------------- */

$t60 = $t00 + $t10 + $t20 + $t30 + $t40 + $t50;
$t61 = $t01 + $t11 + $t21 + $t31 + $t41 + $t51;
$t62 = $t02 + $t12 + $t22 + $t32 + $t42 + $t52;
$t63 = $t03 + $t13 + $t23 + $t33 + $t43 + $t53;
$t64 = $t04 + $t14 + $t24 + $t34 + $t44 + $t54;

/* ----------------------------------- */

$ts0[1] = number_format(round($t01 - $t00, 6), 6);
$ts0[2] = number_format(round($t02 - $t01, 6), 6);
$ts0[3] = number_format(round($t03 - $t02, 6), 6);
$ts0[4] = number_format(round($t04 - $t03, 6), 6);

$min_idx = array_keys($ts0, min($ts0))[0];
foreach ($ts0 as $idx => $val) {
    if ($idx == $min_idx) {
        $ts0[$idx] = "   $val   ";
    } else {
        $ts0[$idx] = "/* $val */";
    }

}

$ts1[1] = number_format(round($t11 - $t10, 6), 6);
$ts1[2] = number_format(round($t12 - $t11, 6), 6);
$ts1[3] = number_format(round($t13 - $t12, 6), 6);
$ts1[4] = number_format(round($t14 - $t13, 6), 6);

$min_idx = array_keys($ts1, min($ts1))[0];
foreach ($ts1 as $idx => $val) {
    if ($idx == $min_idx) {
        $ts1[$idx] = "   $val   ";
    } else {
        $ts1[$idx] = "/* $val */";
    }

}

$ts2[1] = number_format(round($t21 - $t20, 6), 6);
$ts2[2] = number_format(round($t22 - $t21, 6), 6);
$ts2[3] = number_format(round($t23 - $t22, 6), 6);
$ts2[4] = number_format(round($t24 - $t23, 6), 6);

$min_idx = array_keys($ts2, min($ts2))[0];
foreach ($ts2 as $idx => $val) {
    if ($idx == $min_idx) {
        $ts2[$idx] = "   $val   ";
    } else {
        $ts2[$idx] = "/* $val */";
    }

}

$ts3[1] = number_format(round($t31 - $t30, 6), 6);
$ts3[2] = number_format(round($t32 - $t31, 6), 6);
$ts3[3] = number_format(round($t33 - $t32, 6), 6);
$ts3[4] = number_format(round($t34 - $t33, 6), 6);

$min_idx = array_keys($ts3, min($ts3))[0];
foreach ($ts3 as $idx => $val) {
    if ($idx == $min_idx) {
        $ts3[$idx] = "   $val   ";
    } else {
        $ts3[$idx] = "/* $val */";
    }

}

$ts4[1] = number_format(round($t41 - $t40, 6), 6);
$ts4[2] = number_format(round($t42 - $t41, 6), 6);
$ts4[3] = number_format(round($t43 - $t42, 6), 6);
$ts4[4] = number_format(round($t44 - $t43, 6), 6);

$min_idx = array_keys($ts4, min($ts4))[0];
foreach ($ts4 as $idx => $val) {
    if ($idx == $min_idx) {
        $ts4[$idx] = "   $val   ";
    } else {
        $ts4[$idx] = "/* $val */";
    }

}

$ts5[1] = number_format(round($t51 - $t50, 6), 6);
$ts5[2] = number_format(round($t52 - $t51, 6), 6);
$ts5[3] = number_format(round($t53 - $t52, 6), 6);
$ts5[4] = number_format(round($t54 - $t53, 6), 6);

$min_idx = array_keys($ts5, min($ts5))[0];
foreach ($ts5 as $idx => $val) {
    if ($idx == $min_idx) {
        $ts5[$idx] = "   $val   ";
    } else {
        $ts5[$idx] = "/* $val */";
    }

}

$ts6[1] = number_format(round($t61 - $t60, 6), 6);
$ts6[2] = number_format(round($t62 - $t61, 6), 6);
$ts6[3] = number_format(round($t63 - $t62, 6), 6);
$ts6[4] = number_format(round($t64 - $t63, 6), 6);

$min_idx = array_keys($ts6, min($ts6))[0];
foreach ($ts6 as $idx => $val) {
    if ($idx == $min_idx) {
        $ts6[$idx] = "   $val   ";
    } else {
        $ts6[$idx] = "/* $val */";
    }

}

echo "             |    count     |    empty     |     comp     |     cast     |\n";
echo "-------------|--------------|--------------|--------------|--------------|\n";
echo "       Empty |";
echo $ts0[1] . '|';
echo $ts0[2] . '|';
echo $ts0[3] . '|';
echo $ts0[4] . "|\n";

echo "     Uniform |";
echo $ts1[1] . '|';
echo $ts1[2] . '|';
echo $ts1[3] . '|';
echo $ts1[4] . "|\n";

echo "     Integer |";
echo $ts2[1] . '|';
echo $ts2[2] . '|';
echo $ts2[3] . '|';
echo $ts2[4] . "|\n";

echo "      String |";
echo $ts3[1] . '|';
echo $ts3[2] . '|';
echo $ts3[3] . '|';
echo $ts3[4] . "|\n";

echo "       Mixed |";
echo $ts4[1] . '|';
echo $ts4[2] . '|';
echo $ts4[3] . '|';
echo $ts4[4] . "|\n";

echo " Associative |";
echo $ts5[1] . '|';
echo $ts5[2] . '|';
echo $ts5[3] . '|';
echo $ts5[4] . "|\n";

echo "-------------|--------------|--------------|--------------|--------------|\n";
echo "       Total |";
echo $ts6[1] . '|';
echo $ts6[2] . '|';
echo $ts6[3] . '|';
echo $ts6[4] . "|\n";

我认为确定数组是否为空的最好方法是像这样使用count():

if(count($array)) {
    return 'anything true goes here';
}else {
    return 'anything false'; 
}

Count ($gamerow['players'])将为0。

在我看来，索引数组的最简单的方法是:

    if ($array) {
      //Array is not empty...  
    }

如果数组不为空，则数组上的'if'条件将计算为true，如果数组为空则为false。这不适用于关联数组。

如果你想确定你正在测试的变量是否实际上是一个空数组，你可以使用这样的东西:

if ($variableToTest === array()) {
    echo 'this is explicitly an empty array!';
}

已经讨论了许多检查数组是否为空或不包含值的选项

If ($playerlist) {}

If (!empty($playerlist)) {}

If (count($playerlist) > 0) {}

各有利弊。

但还有另一种选择，如果你确定，你的数组只有数字键，从0开始(即，这发生在你爆炸()一个字符串):

if (isset($playerlist[0])) {
  // do something
}

这甚至比其他解还要快一点。