[英]Improved Method of Finding and replacing Strings in an Array in Javascript
I have the following array: 我有以下数组:
["cat", "dog", "cow"]
I want to replace the values of each with a new string. 我想用一个新的字符串替换每个值。
["tiger", "wolf", "diary"]
Currently I am traversing through a for loop and checking to see if a string that needs its name to be changed exists, if it does then I am replacing it with the new value. 当前,我正在遍历for循环,并检查是否存在需要更改其名称的字符串,如果存在,则将其替换为新值。 While a for loop works, I am wondering if there's a nicer way of doing this.
虽然for循环有效,但我想知道是否有更好的方法可以做到这一点。
Assuming you have an object with the replacing to do, you can use Array.map 假设您有一个要替换的对象,则可以使用Array.map
var replace = { 'cat': 'tiger', 'dog': 'wolf', 'cow': 'diary', }; var starter = ["cat", "dog", "cow"]; var final = starter.map(value => replace[value] || value); console.log(final)
If the string is not in the replace
object, replace[value]
is undefined
, so replace[value] || value
如果字符串不在
replace
对象中,则replace[value]
是undefined
,因此replace[value] || value
replace[value] || value
is evaluet do value
itself. replace[value] || value
就是value
本身。
Anyway, the for
is definitely more performing, at least on node.js, accordingly to benchmark.js: 无论如何,
for
肯定至少在node.js上相对于Benchmark.js表现更好:
Array.map x 2,818,799 ops/sec ±1.90% (76 runs sampled)
for array x 9,549,635 ops/sec ±1.86% (79 runs sampled)
Fastest is for array
Here the code I used for the test 这是我用于测试的代码
var Benchmark = require('benchmark');
var suite = new Benchmark.Suite;
suite
.add('Array.map', function() {
var replace = {
'cat': 'tiger',
'dog': 'wolf',
'cow': 'diary',
};
var starter = ["cat", "dog", "cow"];
var final = starter.map(value => replace[value] || value);
})
.add('for array', function() {
var replace = {
'cat': 'tiger',
'dog': 'wolf',
'cow': 'diary',
};
var starter = ["cat", "dog", "cow"];
var final = [];
for (var i = 0; i < starter.length; i++) {
final.push(replace[starter[i]] || starter[i]);
}
})
// add listeners
.on('cycle', function(event) {
console.log(String(event.target));
})
.on('complete', function() {
console.log('Fastest is ' + this.filter('fastest').map('name'));
})
// run async
.run({ 'async': true });
function transform(str){
//logic to transform goes here
}
var massaged = myArr.map(transform);
Maybe thats what youre asking for? 也许这就是您要的?
map reference here : https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map 此处的地图参考: https : //developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map
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