解析字符串中的字符串? [英] Parsing a string within a string?

问题描述

我有一个接受字符串参数的函数，例如:var1=val1 var2=val2 var3='a list of vals'";

I have a function which accepts a string parameter such as: "var1=val1 var2=val2 var3='a list of vals'";

我需要解析这个字符串并挑选出 var/val 组合.这很容易，直到引入诸如 var3='a list of vals' 之类的东西.显然，我无法使用空格分隔符将字符串分解为数组，这让我有点卡住了.我想从这个字符串创建一个数组，并正确分配 var/val 对，如果我有类似 var3 的东西，我该怎么做?

I need to parse this string and pick out the var/val combination's. That is easy enough until introducing something like var3='a list of vals'. Obviously I can't explode the string into an array using a white space delimiter which has me kind of stuck. I want to create an array from this string with the var/val pairs properly assigned, how can I do this in a case where I have something like var3?

推荐答案

如果字符串的格式是一成不变的，您可以执行以下操作:

if the format of the string is set in stone, you could do something like:

$string = "var1=val1 var2=val2 var3='this is a test'";

$vars = array();
$i = 0;
while ($i < strlen($string)) {

    $eqIndex = strpos($string, "=", $i);
    $varName = substr($string, $i, $eqIndex - $i);

    $i = $eqIndex + 1;

    if ($string[$i] == "'") 
    {
        $varEndIndex = strpos($string, "'", ++$i);
    }
    else
    {
        $varEndIndex = strpos($string, " ", $i);
        if ($varEndIndex === FALSE) $varEndIndex = strlen($string);
    }

    $varValue = substr($string, $i, $varEndIndex - $i);

    $vars[$varName] = $varValue;

    $i = $varEndIndex + 1;
}

print_r($vars);

处理引用值中转义字符的更强大的函数:

More robust function that handles escaped chars in the quoted values:

function getVarNameEnd($string, $offset) {

    $len = strlen($string);
    $i = $offset;
    while ($i < $len) {

        if ($string[$i] == "=")
            return $i;
        $i++;
    }

    return $len;
}

function getValueEnd($string, $offset) {

    $len = strlen($string);
    $i = $offset;
    if ($string[$i] == "'") {
        $quotedValue = true;
        $i++;
    }
    while ($i < $len) {

        if ($string[$i] == "\\" && $quotedValue)
            $i++;
        else if ($string[$i] == "'" && $quotedValue)
            return $i + 1;
        else if ($string[$i] == " " && !$quotedValue)
            return $i;
        $i++;
    }

    return $len;
}

function getVars($string) {

    $i = 0;
    $len = strlen($string);
    $vars = array();
    while ($i < $len) {

        $varEndIndex = getVarNameEnd($string, $i);
        $name = substr($string, $i, $varEndIndex - $i);
        $i = $varEndIndex + 1;

        $valEndIndex = getValueEnd($string, $i);
        $value = substr($string, $i, $valEndIndex - $i);
        $i = $valEndIndex + 1;

        $vars[$name] = $value;
    }

    return $vars;
}

$v = getVars("var1=var1 var2='this is a test' var3='this has an escaped \' in it' var4=lastval");
print_r($v);

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