FWIW，我剛剛做了基準(zhǔn)，因為海報沒有這樣做。在PHP 5.3.10 + XDebug上運行。
更新2015-01-22與mcfedr的答案進(jìn)行比較，以獲得沒有XDebug和更新的PHP版本的其他結(jié)果。
function lap($func) {
$t0 = microtime(1);
$numbers = range(0, 1000000);
$ret = $func($numbers);
$t1 = microtime(1);
return array($t1 - $t0, $ret);}function useForeach($numbers) {
$result = array();
foreach ($numbers as $number) {
$result[] = $number * 10;
}
return $result;}function useMapClosure($numbers) {
return array_map(function($number) {
return $number * 10;
}, $numbers);}function _tenTimes($number) {
return $number * 10;}function useMapNamed($numbers) {
return array_map('_tenTimes', $numbers);}foreach (array('Foreach', 'MapClosure', 'MapNamed') as $callback) {
list($delay,) = lap("use$callback");
echo "$callback: $delay\n";}在十幾次嘗試中，我獲得了非常一致的結(jié)果，包括1M數(shù)字：
Foreach：0.7秒
關(guān)閉地圖：3.4秒
功能名稱上的映射：1.2秒。
假設(shè)關(guān)閉時地圖的速度低迷是因為關(guān)閉可能每次都被評估，我也測試過這樣：
function useMapClosure($numbers) {
$closure = function($number) {
return $number * 10;
};
return array_map($closure, $numbers);}但結(jié)果是相同的，證實封閉只評估一次。
以下是三個回調(diào)的操作碼轉(zhuǎn)儲。第一useForeach()：
compiled vars: !0 = $numbers, !1 = $result, !2 = $number
line # * op fetch ext return operands
---------------------------------------------------------------------------------
10 0 > EXT_NOP
1 RECV 1
11 2 EXT_STMT
3 INIT_ARRAY ~0
4 ASSIGN !1, ~0
12 5 EXT_STMT
6 > FE_RESET $2 !0, ->15
7 > > FE_FETCH $3 $2, ->15
8 > OP_DATA
9 ASSIGN !2, $3
13 10 EXT_STMT
11 MUL ~6 !2, 10
12 ASSIGN_DIM !1
13 OP_DATA ~6, $7
14 14 > JMP ->7
15 > SWITCH_FREE $2
15 16 EXT_STMT
17 > RETURN !1
16 18* EXT_STMT
19* > RETURN null
那么 useMapClosure()
compiled vars: !0 = $numbers
line # * op fetch ext return operands
---------------------------------------------------------------------------------
18 0 > EXT_NOP
1 RECV 1
19 2 EXT_STMT
3 EXT_FCALL_BEGIN
4 DECLARE_LAMBDA_FUNCTION '%00%7Bclosure%7D%2Ftmp%2Flap.php0x7f7fc1424173'
21 5 SEND_VAL ~0
6 SEND_VAR !0
7 DO_FCALL 2 $1 'array_map'
8 EXT_FCALL_END
9 > RETURN $1
22 10* EXT_STMT
11* > RETURN null
它調(diào)用的閉包：
compiled vars: !0 = $number
line # * op fetch ext return operands
---------------------------------------------------------------------------------
19 0 > EXT_NOP
1 RECV 1
20 2 EXT_STMT
3 MUL ~0 !0, 10
4 > RETURN ~0
21 5* EXT_STMT
6* > RETURN null
那么useMapNamed()功能：
compiled vars: !0 = $numbers
line # * op fetch ext return operands
---------------------------------------------------------------------------------
28 0 > EXT_NOP
1 RECV 1
29 2 EXT_STMT
3 EXT_FCALL_BEGIN
4 SEND_VAL '_tenTimes'
5 SEND_VAR !0
6 DO_FCALL 2 $0 'array_map'
7 EXT_FCALL_END
8 > RETURN $0
30 9* EXT_STMT
10* > RETURN null
以及它調(diào)用的命名函數(shù)_tenTimes()：
compiled vars: !0 = $number
line # * op fetch ext return operands
---------------------------------------------------------------------------------
24 0 > EXT_NOP
1 RECV 1
25 2 EXT_STMT
3 MUL ~0 !0, 10
4 > RETURN ~0
26 5* EXT_STMT
6* > RETURN null
