检查字符串是否包含与正则表达式匹配的子字符串

Question

I'm writing a script to check if there's occurence of amex credit card number inside a string.

My code looks like this:

let amexRegex= /^3[47][0-9]{13}$/;

if(text.search(amexRegex) != -1){
    console.log('Found!');
} else {
    console.log('Not found!');
}

When I set text to '378734493671000' (a valid amex credit card number), script prints out Found! , but if I keep that same text and add some text arround it, like this: '378734493671000 ABCDEFG' , it prints out Not found! .

What should I change in order to find occurence of substring matching the regex? I don't need a index of substring matching the regex, just true\\false.

Answer 1

The ^ and $ restrict matching to beginning and end of string, respectively. It's probably enough to remove those.

Answer 2

您只需要删除分别匹配stat和行尾的^和$ ：

let amexRegex= /3[47][0-9]{13}/;

Answer 3

let amexRegex = /3[47][0-9]{13}/

if(amenxRegex.test(text) {
  console.log('Found!')
} else {
  console.log('Not found!')
}

Answer 4

Pay attention that only removing ^ and $ can lead to incorrect matches, such as longer numeric strings. You better replace them by word boundaries:

\b3[47][0-9]{13}\b

Demo