javascript - About interception of strings

Question

For example, there is a string a = "8px";
The number of digits in the number is not necessarily certain. If I want to intercept the number, I want to use a.substring(0,a.indexOf("p")). I originally wanted to use a.substring(0,-2); But after checking, I found out that the substring parameter cannot be a negative number, but I think a.substring(0,a.indexOf("p")) is a bit troublesome. Is there a more direct optimization method?

Answer 1

var a="88px";
If the format is the same, the first parts are numbers and only the numbers need to be extracted, you can use:
parseInt(a);//88

Answer 2

Use regular rules

console.log('8px'.match(/(\d+)/)[0])

Answer 3

The first one can use the substring method: a.substring(0,a.length-2)
The second one can use regular expressions: var a='8px';a.replace(/px$/ig,'' )

Answer 4

var a = '8px';
a.slice(0,-2);

Answer 5

parseInt,parseFloat,slice,regexp

Answer 6

var str1 = "8px",
    str2 = "88px",
    str3 = "888px",
    str4 = "8.88px";
    
str1.replace(/(.*)px/, "$1"); //8
str2.replace(/(.*)px/, "$1"); //88
str3.replace(/(.*)px/, "$1"); //888
str4.replace(/(.*)px/, "$1"); //8.88

Answer 7

It is most convenient to use regular expressions

var reg = /([\d\.]+)px/; // 使用这个正则匹配
var arr = ['8px', '18px', '28px', '0.08px']
for (let i = 0, len = arr.length; i < len; i++) {
    console.log(arr[i], arr[i].match(reg)[1]);  // 结果arr[i].match(reg)[1]
}

Answer 8

I’m speechless for you guys, can’t I use parseInt, parseFloat