Question

我有这段代码：

<?php
set_time_limit(0);
ini_set('display_errors','On');
function ImportCSV2Array($filename)
{
    $row = 0;
    $col = 0;

    $handle = @fopen($filename, "r");
    if ($handle) 
    {
        while (($row = fgetcsv($handle, 4096,";")) !== false) 
        {
            if (empty($fields)) 
            {
                $fields = $row;
                continue;
            }

            foreach ($row as $k=>$value) 
            {
                $results[$col][$fields[$k]] = $value;
            }
            $col++;
            unset($row);
        }
        if (!feof($handle)) 
        {
            echo "Error: unexpected fgets() failn";
        }
        fclose($handle);
    }

    return $results;
}
include_once("../config.php");
$nome_file = "./".$_GET['file'];

$csvArray = ImportCSV2Array($nome_file);
$i = 0;
foreach ($csvArray as $row=>$value)
{

$mp = array("1","2","3","4","5","7","11","12","13","16","17","18","26","27","28","33","34","42","43","45");
$fin = array("0","1","2","4","8","15","20","21","22","30","31","32","40","41","42","52","54","81","82","91");
            $codEvento = str_replace($mp, $fin, trim($value['CODEV']));

        if($value['INDEX']==0){
            echo $codEvento."-".$value['CODEV'].";".$value['COGNNOME'].";".$value['TEMPO'].";".$value['ANNO'].";".$value['DATA']."<br>";

        }
    }

?>

当我尝试用str_replace转换$ fin数组中的$ mp数组时，我遇到了问题。

如果我的$ value ['CODEV']第一次包含“12”，它将替换为23，因为1被2和2替换为3.为什么它看到“12”字符串，这样我们两个不同的字符串？为什么它不能用“21”代替“12”？

Answer 1

当您提供数组作为搜索＆amp;将参数替换为str_replace，它将遍历并用输入中相应的替换字符串替换每个找到的搜索字符串。

在你的情况下，＆＃34; 12＆＃34;是输入，所以它需要的第一个动作是替换＆＃34; 1＆＃34;使用＆＃34; 0＆＃34;，保留＆＃34; 02＆＃34;的值。接下来它找到＆＃34; 2＆＃34;并将其替换为＆＃34; 1＆＃34;给你一个值＃34; 01＆＃34;。没有更多的匹配，所以你最终会得到＆＃34; 01＆＃34;。

如果您重新订购了搜索/替换对，那么＆＃34; 12＆＃34;显示在列表的前面，您仍然会得到错误的值。第一次搜索将取代＆＃34; 12＆＃34;用＆＃34; 21＆＃34; （你想要什么），但后来的传球会取代＆＃34; 1＆＃34;用＆＃34; 0＆＃34;和＆＃34; 2＆＃34;用＆＃34; 1＆＃34;离开你＆＃34; 10＆＃34;这一次。

问题是你的搜索字符串数组会自行处理。如果要完全替换输入字符串，那么循环可能会更好，如下所示：

$mp = array("1","2","3","4","5","7","11","12","13","16","17","18","26","27","28","33","34","42","43","45");
$fin = array("0","1","2","4","8","15","20","21","22","30","31","32","40","41","42","52","54","81","82","91");
$input = "12";
$output = "?";
for ($i=0; $i<count($mp); $i++) {
    if ($input === $mp[$i]) {
        $output = $fin[$i];
        break;
    }
}
echo $output

PHP看到一个字符串，如单个字符

1 个答案: