如何在 javascript 中检索文本中重复字符串的第一个字符的索引？

Question

i must obtain in javascript the first index of the term "Query Response" that appears multiple times in "output_pacs" that is a variable in which is allocated the content, that is a file with multiple rows and columns.

var strutturaIndici=[];
for(var i=0;i< output.length;i++)
{
    var indice_primo_carattere= output(i).indexOf("Query Response");
    strutturaIndici.push(indice_primo_carattere);
}

logger.debug('StrutturaIndici:' +strutturaIndici);

The problem is that the term "Query Response" appears to me multiple times in this file, and i must obtain the first index of this term every time that it appears in this content with this code, in the console, i don't obtain the indexes, what can i do? in the console i obtain this:

[2021-01-30 12:53:20,002]  DEBUG  (js-connector:?): StrutturaIndici:

Answer 1

Just make a loop and call indexOf everytime with the lastIndex as a start to search for next term. And if indexOf returns -1, then break out of the loop.

You may look here , how the indexOf function is defined on strings

 var output_pacs = "test Query Response Query Response hello Query Response" var indices = []; var lastIndex = 0; while (true) { lastIndex = output_pacs.indexOf("Query Response", lastIndex + 1); if (lastIndex === -1) { // No more found break; } indices.push(lastIndex); } console.log('StrutturaIndici:' + indices);

Answer 2

Try Using:

 function getIndexes(searchStr, str) { let searchStrLen = searchStr.length; if (searchStrLen == 0) { return []; } let startIndex = 0, index, indices = []; str = str.toLowerCase(); searchStr = searchStr.toLowerCase(); while ((index = str.indexOf(searchStr, startIndex)) > -1) { indices.push(index); startIndex = index + searchStrLen; } return indices; } let a = getIndexes("Query Response", "Query Response Happy New Year Query Response Happy Query Response New Year Happy Pongal Query Response New Year"); console.log(a);