I am writing a regex to match number of digits. The whole string can have atleast 6 digits and can have spaces and dashes.

for e.g.

123-45 6  valid
123456    valid
123-56    Invalid

Initially i wrote a regex that took care of minimum of 6 chars in the string. However, it did not work as it was counting the dashes and spaces as part of 6.

[\d\s-]{6,}

Tried

[\d]{6,}[\s-]

even this one is not working. Can you suggest how to fix this.

Another Attempt:

[[\d]{6,}[\s]*[-]*]

I am writing a regex to match number of digits. The whole string can have atleast 6 digits and can have spaces and dashes.

for e.g.

123-45 6  valid
123456    valid
123-56    Invalid

Initially i wrote a regex that took care of minimum of 6 chars in the string. However, it did not work as it was counting the dashes and spaces as part of 6.

[\d\s-]{6,}

Tried

[\d]{6,}[\s-]

even this one is not working. Can you suggest how to fix this.

Another Attempt:

[[\d]{6,}[\s]*[-]*]

• javascript
• regex

• 3 (?:\d[\s\-]*){6} – Siguza Commented Jul 9, 2016 at 22:02
• could you preprocess the string before you match? the issue is that the {6,} says 6 matches, not 6 digits, so the last one has 6 matches (with the dash) and the top one matches because of 123-45` not because of the 6 digits. – mr rogers Commented Jul 9, 2016 at 22:02
• @Siguza that works !! Can you explain as well ? – CodeMonkey Commented Jul 9, 2016 at 22:03

3 Answers 3

To check for the presence of at least 6 digits you can use /(?:\d\D*){6,}/. If you also want it to only allow space and dash, you could adjust the pattern to /^[ -]*(?:\d[ -]*){6,}$/

The solution using String.replace and String.match functions:

var isValid = function(str){
    var match = str.replace(/[\s-]/g, "").match(/^\d{6,}$/);
    return Boolean(match);
};

console.log(isValid("123-45 6"));  // true
console.log(isValid("12345678"));  // true
console.log(isValid("123-56"));    // false
console.log(isValid("123-567<"));  // false

You can do it either like this (accepts spaces and dashes at the end):

(\d[\s-]*){6,}

or like this (only dashes and spaces between digits):

(\d[\s-]*){5,}\d