我试图用多个其他单词替换字符串中的多个单词。字符串是“我有一只猫，一只狗和一只山羊。”
然而，这并不会产生“我有一只狗、一只山羊和一只猫”，而是产生“我有一只猫、一只猫和一只猫”。是否有可能在JavaScript中同时用多个其他字符串替换多个字符串，以便产生正确的结果?
var str = "I have a cat, a dog, and a goat.";
str = str.replace(/cat/gi, "dog");
str = str.replace(/dog/gi, "goat");
str = str.replace(/goat/gi, "cat");
//this produces "I have a cat, a cat, and a cat"
//but I wanted to produce the string "I have a dog, a goat, and a cat".
当前回答
一种可能的解决方案是使用mapper表达式函数。
const regex = /(?:cat|dog|goat)/gmi;
const str = `I have a cat, a dog, and a goat.`;
let mapper = (key) => {
switch (key) {
case "cat":
return "dog"
case "dog":
return "goat";
case "goat":
return "cat"
}
}
let result = str.replace(regex, mapper);
console.log('Substitution result: ', result);
//Substitution result1: I have a dog, a goat, and a cat.
其他回答
<!DOCTYPE html>
<html>
<body>
<p id="demo">Mr Blue
has a blue house and a blue car.</p>
<button onclick="myFunction()">Try it</button>
<script>
function myFunction() {
var str = document.getElementById("demo").innerHTML;
var res = str.replace(/\n| |car/gi, function myFunction(x){
if(x=='\n'){return x='<br>';}
if(x==' '){return x=' ';}
if(x=='car'){return x='BMW'}
else{return x;}//must need
});
document.getElementById("demo").innerHTML = res;
}
</script>
</body>
</html>
以防有人想知道为什么原来海报上的解决方案不管用:
var str = "I have a cat, a dog, and a goat.";
str = str.replace(/cat/gi, "dog");
// now str = "I have a dog, a dog, and a goat."
str = str.replace(/dog/gi, "goat");
// now str = "I have a goat, a goat, and a goat."
str = str.replace(/goat/gi, "cat");
// now str = "I have a cat, a cat, and a cat."
使用编号的物品，防止再次更换。 如
let str = "I have a %1, a %2, and a %3";
let pets = ["dog","cat", "goat"];
then
str.replace(/%(\d+)/g, (_, n) => pets[+n-1])
它的工作原理:- %\d+查找跟在%后面的数字。括号表示数字。
这个数字(作为字符串)是lambda函数的第二个参数n。
+n-1将字符串转换为数字，然后减去1以索引宠物数组。
然后将%数字替换为数组下标处的字符串。
/g导致lambda函数被重复调用，每个数字被替换为数组中的字符串。
在现代JavaScript中:-
replace_n=(str,...ns)=>str.replace(/%(\d+)/g,(_,n)=>ns[n-1])
所有的解决方案都很好，除了应用于闭包的编程语言(如Coda, Excel，电子表格的REGEXREPLACE)。
我下面的两个原始解决方案只使用1个连接和1个正则表达式。
方法#1:查找替换值
其思想是，如果替换值不在字符串中，则附加替换值。然后，使用一个regex，我们执行所有需要的替换:
var str = "我有一只猫，一只狗，和一只山羊。"; STR = (STR +"||||猫，狗，山羊").replace( /猫(? = [\ s \ s] *(狗))|狗(? = [\ s \ s] *(山羊))|山羊(? = [\ s \ s] *(猫 ))|\|\|\|\|.* $ / gi, " $ 1 $ 2 $ 3”); document.body.innerHTML = str;
解释:
cat(?=[\s\S]*(dog)) means that we look for "cat". If it matches, then a forward lookup will capture "dog" as group 1, and "" otherwise. Same for "dog" that would capture "goat" as group 2, and "goat" that would capture "cat" as group 3. We replace with "$1$2$3" (the concatenation of all three groups), which will always be either "dog", "cat" or "goat" for one of the above cases If we manually appended replacements to the string like str+"||||cat,dog,goat", we remove them by also matching \|\|\|\|.*$, in which case the replacement "$1$2$3" will evaluate to "", the empty string.
方法#2:查找替换对
方法#1的一个问题是它一次不能超过9个替换，这是反向传播组的最大数量。 方法#2声明不只是附加替换值，而是直接替换:
var str = "我有一只猫，一只狗，和一只山羊。"; str = (str + " | | | |,猫= >狗,狗= >山羊,山羊= >猫”).replace ( / (\ b \ w + \ b) (? = [\ s \ s] * \ 1 =>([^,]*))|\|\|\|\|.* $ / gi, " $ 2 "); document.body.innerHTML = str;
解释:
(str+"||||,cat=>dog,dog=>goat,goat=>cat") is how we append a replacement map to the end of the string. (\b\w+\b) states to "capture any word", that could be replaced by "(cat|dog|goat) or anything else. (?=[\s\S]*...) is a forward lookup that will typically go to the end of the document until after the replacement map. ,\1=> means "you should find the matched word between a comma and a right arrow" ([^,]*) means "match anything after this arrow until the next comma or the end of the doc" |\|\|\|\|.*$ is how we remove the replacement map.
通过使用原型函数，我们可以通过传递对象的键和值以及可替换的文本轻松地进行替换
String.prototype.replaceAll =函数(obj keydata =“关键”){ const键= keydata.split(关键); 返回Object.entries (obj) .reduce((,(关键,val)) = > a.replace(“${键[0]}${关键}${键[1]}',val),) ｝ Const data=' hidden dv SDC sd ${yathin} ${ok}' console.log (data.replaceAll ({yathin: 12,好的:“嗨”},“${关键}”))
