就是把原來(lái)的數(shù)組中的數(shù)都“拆”成“單”位的。
下面是自己寫(xiě)的一個(gè)函數(shù)：
復(fù)制代碼代碼如下:
function splitStrToArray_mine($array)
{
$new_array = array();
foreach($array as $value)
{
$value = (string)$value;
$len = strlen($value);
for($i = 0; $i < $len; $i ++){
array_push($new_array, $value{$i});
}
}
return $new_array;
}
測(cè)試了一下，還是可以執(zhí)行的，如下調(diào)用：
復(fù)制代碼代碼如下:
//測(cè)試數(shù)組
$data = array(12, 43, 87, 45, 98, 74, 83, 67, 12);
var_dump(splitStrToArray_mine($data));
輸出結(jié)果為：
復(fù)制代碼代碼如下:
array(18) {
[0]=>
string(1) "1"
[1]=>
string(1) "2"
[2]=>
string(1) "4"
[3]=>
string(1) "3"
[4]=>
string(1) "8"
[5]=>
string(1) "7"
[6]=>
string(1) "4"
[7]=>
string(1) "5"
[8]=>
string(1) "9"
[9]=>
string(1) "8"
[10]=>
string(1) "7"
[11]=>
string(1) "4"
[12]=>
string(1) "8"
[13]=>
string(1) "3"
[14]=>
string(1) "6"
[15]=>
string(1) "7"
[16]=>
string(1) "1"
[17]=>
string(1) "2"
}
雖然執(zhí)行的不錯(cuò)，但是看看標(biāo)準(zhǔn)答案就會(huì)讓你大吃一驚的，函數(shù)中就一句話，如下：
復(fù)制代碼代碼如下:
//標(biāo)準(zhǔn)函數(shù)
function splitStrToArray($array)
{
return str_split(implode("", $array));
}
于是寫(xiě)了腳本來(lái)測(cè)試自己的和標(biāo)準(zhǔn)的函數(shù)的運(yùn)行效率差距，里面有一個(gè) microtime_float() 函數(shù)用來(lái)提供精確時(shí)間的支持：
復(fù)制代碼代碼如下:
//測(cè)量時(shí)間的函數(shù)
function microtime_float()
{
list($usec, $sec) = explode(" ", microtime());
return ((float)$usec + (float)$sec);
}
//自定義函數(shù)
function splitStrToArray_mine($array)
{
$new_array = array();
foreach($array as $value)
{
$value = (string)$value;
$len = strlen($value);
for($i = 0; $i < $len; $i ++){
array_push($new_array, $value{$i});
}
}
return $new_array;
}
//標(biāo)準(zhǔn)函數(shù)
function splitStrToArray($array)
{
return str_split(implode("", $array));
}
//測(cè)試數(shù)組
$data = array(12, 43, 87, 45, 98, 74, 83, 67, 12);
//開(kāi)始測(cè)試
$mine_start = microtime_float();
splitStrToArray_mine($data);
$mine_end = microtime_float();
//標(biāo)準(zhǔn)函數(shù)調(diào)用
$sta_start = microtime_float();
splitStrToArray($data);
$sta_end = microtime_float();
echo "自己的函數(shù)調(diào)用運(yùn)行時(shí)間為：" . (float)($mine_end - $mine_start) . " S <br />";
echo "標(biāo)準(zhǔn)的函數(shù)調(diào)用運(yùn)行時(shí)間為：" . (float)($sta_end - $sta_start) . " S <br />";
$multiple = (int)((float)($mine_end - $mine_start) / (float)($sta_end - $sta_start));
echo "前者是后者的：" . $multiple . " 倍！";
來(lái)看看輸出結(jié)果：
自己的函數(shù)調(diào)用運(yùn)行時(shí)間為：9.3936920166E-005 S
標(biāo)準(zhǔn)的函數(shù)調(diào)用運(yùn)行時(shí)間為：2.69412994385E-005 S
前者是后者的：3 倍！
多次刷新頁(yè)面的話，可以發(fā)現(xiàn)標(biāo)準(zhǔn)函數(shù)的執(zhí)行效率基本上是自己的函數(shù)的 3 倍！當(dāng)然，標(biāo)準(zhǔn)的函數(shù)中使用了 PHP 的內(nèi)置函數(shù): str_split()，implode()，所以要比自己寫(xiě)函數(shù)快得多，對(duì) str_split() 函數(shù)沒(méi)有印象？來(lái)看看手冊(cè)解釋?zhuān)?nbsp;
str_split -- Convert a string to an array(將一個(gè)字符串轉(zhuǎn)換成數(shù)組)
函數(shù)描述：
array str_split ( string string [, int split_length] )
復(fù)制代碼代碼如下:
Converts a string to an array. If the optional split_length parameter is specified, the returned array will be broken down into chunks with each being split_length in length, otherwise each chunk will be one character in length.
FALSE is returned if split_length is less than 1. If the split_length length exceeds the length of string, the entire string is returned as the first (and only) array element.
例 1. Example uses of str_split()
復(fù)制代碼代碼如下:
<?php
$str = "Hello Friend";
$arr1 = str_split($str);
$arr2 = str_split($str, 3);
print_r($arr1);
print_r($arr2);
?>
Output may look like:
復(fù)制代碼代碼如下:
Array
(
[0] => H
[1] => e
[2] => l
[3] => l
[4] => o
[5] =>
[6] => F
[7] => r
[8] => i
[9] => e
[10] => n
[11] => d
)
Array
(
[0] => Hel
[1] => lo
[2] => Fri
[3] => end
)
