Question

我无法弄清楚为什么我的循环无法在myName中找到textToSearch的每一次出现。如果它接近textToSearch的开头，它只能找到一个匹配项。

var textToSearch = "Aaron blue red Aaron green Aaron yellow Aaron";
var myName = "Aaron";
var hits = [];
for(i = 0; i < textToSearch.length; i++){
   if(textToSearch.substring(i, myName.length) === myName){ 
     hits.push(textToSearch.substring(i, myName.length));
   }
}
if(hits.length === 0){
   console.log("Your name wasn't found!");
} else {
   console.log("Your name was found " + hits.length + " times.");
   console.log(hits);
}

Answer 1

您需要从i子串到i + myName.length。

var textToSearch = "Aaron blue red Aaron green Aaron yellow Aaron";
var myName = "Aaron";
var hits = [];
for(var i = 0; i < textToSearch.length; i++){
   if(textToSearch.substring(i, i + myName.length) === myName){ 
     hits.push(textToSearch.substring(i, i + myName.length));
   }
}
if(hits.length === 0){
   console.log("Your name wasn't found!");
} else {
   console.log("Your name was found " + hits.length + " times.");
   console.log(hits);
}

BTW有更好的方法来计算发生次数

var textToSearch = "Aaron blue red Aaron green Aaron yellow Aaron";

console.log((textToSearch.match(/Aaron/g) || []).length)

Answer 2

另一种解决方案是使用indexOf。它将偏移量作为第二个参数。

var textToSearch = "Aaron blue red Aaron green Aaron yellow Aaron";
var myName = "Aaron";
var hits = 0;
var lastIndex = 0;

while(lastIndex != -1){
   lastIndex = textToSearch.indexOf(myName, lastIndex);
   if (lastIndex != -1) {
     hits++;
     lastIndex++;
   } // Search at the next index
}

if(hits === 0){
   console.log("Your name wasn't found!");
} else {
   console.log("Your name was found " + hits + " times.");
}

使用for循环在另一个内部查找一个字符串

2 个答案: