Javascript Regex - 在for循环中匹配字符串后的int

Question

我正在尝试捕获与字符串 txt 中的关键字相关的计数。所有关键字都提前加载到数组中。

此代码在 jquery/javascript 中。我不能对字符串关键字进行硬编码，这就是它们存储在数组中的原因。请帮助我在循环中的关键字变量之前和/或之后找到代替“Reg Expression”的内容。

html br 可用于在循环的该迭代中结束该正则表达式匹配。

试图以 keywordCount = "2, 5, 11" 结尾

//String I need to search through
var txt = "Edit Req'd2<br>Errors5<br>Pndg App11<br>";

//array of keywords I can use to find associated counts to keywords
var keyword = ["Edit Req'd", "Errors", "Pndg App"];

//empty string declared before loop
var keywordCount = '';

for (i = 0; i < keyword.length; i++) {

    // takes the comma off end of first entry in array
    // might not be needed or another method might be better?
    keyword[i] = $.trim(keyword[i]);

    //regex expression generated using keyword and unknown expression 
    var regexmatch = RegExp("Reg Expression" + keyword + "Reg Expression")

    //use regex expression to generate string containing counts
    keywordCount += (txt.match(regexmatch)) + ",";
}

Answer 1

这是一个可以帮助您实现所需输出的示例。

//String I need to search through
var txt = "Edit Req'd2<br>Errors5<br>Pndg App11<br>";

//array of keywords I can use to find associated counts to keywords
var keyword = ["Edit Req'd", "Errors", "Pndg App"];

//empty string declared before loop
var keywordCount = '';
var i = 0;
var keywordCount = "";
var splittedValue = "";
while (i < keyword.length) {
    if (txt.indexOf(keyword[i]/i)) {
        splittedValue = txt.split(keyword[i]);
        if (keywordCount === "") {
            keywordCount = splittedValue[1].split("<br>")[0];
        } else {
            keywordCount += ", " + splittedValue[1].split("<br>")[0];
        }
    }
    i += 1;
}
console.log(keywordCount);

Answer 2

我会使用数字/数字范围来匹配数字（[0-9]；这是非常基本的正则表达式），并使用组来匹配任何关键字：

• 任意位数：[0-9]+
• 您的任何关键字：(something|somethingelse|other)

您也可以使用捕获组让match() 分别返回它们：

var keyword = ["Edit Req'd", "Errors", "Pndg App"];
var regexmatch = RegExp('(\b' + keyword.join('|') + ')([0-9]+)', 'g')

（请注意，我们使用单词边界 \b 来确保关键字不是较长单词的一部分，并且全局的 'g' 标志表示我们想要多个结果）

现在，match() 只会匹配一个结果，并且我们希望匹配每个关键字，所以我们将使用 exec() 代替：

var txt = "Edit Req'd2<br>Errors5<br>Pndg App11<br>";
var keyword = ["Edit Req'd", "Errors", "Pndg App"];
var regex = RegExp('(\b' + keyword.join('|') + ')([0-9]+)', 'g')

var match = regex.exec( txt ); // ...find the first match
var numbers = [];

while ( match !== null ) {
  numbers.push( match[ 2 ]); // #0 of exec() its return-value is the result as a whole: "Edit Req'd2"
                             // #1 is the value of the first capture-group: "Edit Req'd"
                             // #2 is the value of the second capture-group: "2"

  match = regex.exec( txt ); // ...find the next match
}

console.log("the numbers are:", numbers);

最后，请注意正则表达式可能看起来很酷，它们是not always the fastest（性能方面）。如果性能很重要，您可以使用（例如）indexOf()。

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从您的问题来看，您似乎可以稍微复习一下您对正则表达式的了解。周围有很多文章（只需搜索“正则表达式基础知识”或“regex 101”）——比如这个： https://medium.com/factory-mind/regex-tutorial-a-simple-cheatsheet-by-examples-649dc1c3f285*