Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
302 views
in Technique[技术] by (71.8m points)

formatting - How to print a number with commas as thousands separators in JavaScript

I am trying to print an integer in JavaScript with commas as thousands separators. For example, I want to show the number 1234567 as "1,234,567". How would I go about doing this?

Here is how I am doing it:

function numberWithCommas(x) {
    x = x.toString();
    var pattern = /(-?d+)(d{3})/;
    while (pattern.test(x))
        x = x.replace(pattern, "$1,$2");
    return x;
}

Is there a simpler or more elegant way to do it? It would be nice if it works with floats also, but that is not necessary. It does not need to be locale-specific to decide between periods and commas.


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

I used the idea from Kerry's answer, but simplified it since I was just looking for something simple for my specific purpose. Here is what I did:

function numberWithCommas(x) {
    return x.toString().replace(/B(?=(d{3})+(?!d))/g, ",");
}

function numberWithCommas(x) {
    return x.toString().replace(/B(?<!.d*)(?=(d{3})+(?!d))/g, ",");
}

function test(x, expect) {
    const result = numberWithCommas(x);
    const pass = result === expect;
    console.log(`${pass ? "?" : "ERROR ====>"} ${x} => ${result}`);
    return pass;
}

let failures = 0;
failures += !test(0,        "0");
failures += !test(100,      "100");
failures += !test(1000,     "1,000");
failures += !test(10000,    "10,000");
failures += !test(100000,   "100,000");
failures += !test(1000000,  "1,000,000");
failures += !test(10000000, "10,000,000");
if (failures) {
    console.log(`${failures} test(s) failed`);
} else {
    console.log("All tests passed");
}
.as-console-wrapper {
    max-height: 100% !important;
}

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

1.4m articles

1.4m replys

5 comments

57.0k users

...