如何从JavaScript中的字符串变量中提取IP地址

Question

i have written bellow code in javascript

function reg()
{
    var a="ec2-54-234-174-228.compute-1.amazonaws.com";
    var r = a.match(/\-[0-9]*/g);
    alert(r);
}

i got output like -54,-234,-174,-228,-1 but i need to extract only 54-234-174-228 IP address from variable a.

Answer 1

Try this:

function reg()
{
    var a="ec2-54-234-174-228.compute-1.amazonaws.com";
    var r = a.match(/\-[0-9-]*/g);
    alert(r[0].substring(1,r[0].length));
}

a.match(/\\-[0-9-]*/g); will return [-54-234-174-228,-1] . Getting the first element and removing - from the beginning you get what your IP. You can also add this:

alert(r[0].substring(1,r[0].length).replace(/-/g, '.'));

to return it in IP shape: 54.234.174.228

Answer 2

Try this regexp: /[0-9]{1,3}(-[0-9]{1,3}){3}(?=\\.)/

It matches a series of 4 numbers between 1 and 3 digits separated by -, which must be followed by a dot.

Answer 3

get the index of first "." then slice

function reg()
{
    var a="ec2-54-234-174-228.compute-1.amazonaws.com";
    var r = a.indexOf(".");
    alert(a.slice(0,r));
}

Answer 4

"ec2-54-234-174-228.compute-1.amazonaws.com".split('.')[0].split('-').slice(1,5).join('.')

Answer 5

就您而言，您可以简单地使用以下模式：

var r = a.match(/([^a-z][0-9]+\-[0-9]+\-[0-9]+\-[0-9]+)/g);

Answer 6

您可以使用此正则表达式

"(\\d{2}-\\d{3}-\\d{3}-\\d{3})+"

Answer 7

One more example:

function reg() {
    var a="ec2-54-234-174-228.compute-1.amazonaws.com";
    var re = /-(\d+)/ig
    var arr = [];
    while(digit = re.exec(a)) arr.push(digit[1]);
    arr = arr.slice(0,4);

    alert(arr)
}