我需要帮助将keys分配给PHP中的array。
我的代码是
//First I make an array of a csv file
$file="C:'path-to-csv'file.csv";
$csv= file_get_contents($file);
$array = array_map("str_getcsv", explode("'n", $csv));
array:
//echo json_encode($array);
["0","20150717","2:57:00","1437145020","1.56084","1.56096","1.56084","1.56094","5"],
["1","20150717","2:56:00","1437144960","1.56071","1.56089","1.56071","1.56089","9"],
["2","20150717","2:55:00","1437144900","1.5607","1.5607","1.56064","1.56064","2"], //continue
从$array的结果，我需要分配一个特定的key到一个特定的列，并创建一个新的array"$newArray"。因此，结果如下所示:
//$newArray should print:
"ID" : [0, 1, 2], //I would like delete this value
"n" : [20150717, 20150717, 20150717], //I would like delete this value
"d" : [2:57:00, 2:56:00, 2:55:00], //I would like delete this value
"t" : [1437145020, 1437144960, 1437144900], //column 4
"o" : [1.56084, 1.56071, 1.5607], //column 5
"h" : [1.56096, 1.56089, 1.5607], // column 6
"l" : [1.56084, 1.56071, 1.56064], // column 7
"c" : [1.56094, 1.56089, 1.56064], //column 8
"v" : [5, 9, 2] //column 9
我试过通过循环和一些函数，如array_fill_keys和array_column，但我不能得到想要的结果。如果你能帮助我，我将非常感激，$array有超过1000个条目，所以优化代码执行速度是非常重要的，老实说超出了我的知识，我在谷歌没有看到任何东西来帮助我完成这一点。谢谢你的时间，抱歉我的语法错误。
如果你使用PHP 5.5，你可以使用array_column:
$newArray = array(
't' => array_column($array, 3),
'o' => array_column($array, 4),
'h' => array_column($array, 5),
...
);
如果你使用的是旧版本的PHP，你可以找到它的PHP实现:Is there a function to extract a 'column'PHP中的数组?
EDIT基本上，当您无法使用array_column时，此解决方案可以在5.5中使用。
对于foreach循环来说，超过1000个条目似乎并不多。
$keys = array('t','o','h','l','c','v');
$newArray = array();
foreach ($array as $j) {
$r = array_slice($j, 3);
foreach ($r as $i => $v) $newArray[$keys[$i]][] = $v*1;
}
Json编码的结果将是
"t":[1437144900,1437144900,1437145020],
"o":[1.5607,1.5607,1.56084],
"h":[1.5607,1.5607,1.56096],
"l":[1.56064,1.56064,1.56084],
"c":[1.56064,1.56064,1.56094],
"v":[2,2,5]
运行包含10,000个条目的数组
0.020426
你可以在PhpFiddle上测试自己