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".
这招对我很管用:
String.prototype.replaceAll = function(search, replacement) {
var target = this;
return target.replace(new RegExp(search, 'g'), replacement);
};
function replaceAll(str, map){
for(key in map){
str = str.replaceAll(key, map[key]);
}
return str;
}
//testing...
var str = "bat, ball, cat";
var map = {
'bat' : 'foo',
'ball' : 'boo',
'cat' : 'bar'
};
var new = replaceAll(str, map);
//result: "foo, boo, bar"
在这个实例中,这可能不能满足您的确切需求,但我发现这是一种有用的方法,可以替换字符串中的多个参数,作为通用解决方案。它将替换参数的所有实例,无论它们被引用了多少次:
String.prototype.fmt = function (hash) {
var string = this, key; for (key in hash) string = string.replace(new RegExp('\\{' + key + '\\}', 'gm'), hash[key]); return string
}
你可以这样调用它:
var person = '{title} {first} {last}'.fmt({ title: 'Agent', first: 'Jack', last: 'Bauer' });
// person = 'Agent Jack Bauer'
注意!
如果您正在使用动态提供的映射,这里的解决方案都不够!
在这种情况下,有两种解决方法:(1)使用分割连接技术,(2)使用正则表达式和特殊字符转义技术。
这是一个分割连接技术,它比另一个快得多(至少快50%):
var str = "I have {abc} a c|at, a d(og, and a g[oat] {1} {7} {11."
var mapObj = {
'c|at': "d(og",
'd(og': "g[oat",
'g[oat]': "c|at",
};
var entries = Object.entries(mapObj);
console.log(
entries
.reduce(
// Replace all the occurrences of the keys in the text into an index placholder using split-join
(_str, [key], i) => _str.split(key).join(`{${i}}`),
// Manipulate all exisitng index placeholder -like formats, in order to prevent confusion
str.replace(/\{(?=\d+\})/g, '{-')
)
// Replace all index placeholders to the desired replacement values
.replace(/\{(\d+)\}/g, (_,i) => entries[i][1])
// Undo the manipulation of index placeholder -like formats
.replace(/\{-(?=\d+\})/g, '{')
);
这一个,是Regex特殊字符转义技术,它也有用,但慢得多:
var str = "I have a c|at, a d(og, and a g[oat]."
var mapObj = {
'c|at': "d(og",
'd(og': "g[oat",
'g[oat]': "c|at",
};
console.log(
str.replace(
new RegExp(
// Convert the object to array of keys
Object.keys(mapObj)
// Escape any special characters in the search key
.map(key => key.replace(/[-[\]{}()*+?.,\\^$|#\s]/g, '\\$&'))
// Create the Regex pattern
.join('|'),
// Additional flags can be used. Like `i` - case-insensitive search
'g'
),
// For each key found, replace with the appropriate value
match => mapObj[match]
)
);
后者的优点是,它也可以用于不区分大小写的搜索。