I need to create a Regular Expression for 13 characters alphanumeric string having exactly 3 characters and 10 numbers.

I am trying this:

^(?=.*\d{10})(?=.*[a-zA-Z]{3})[0-9a-zA-Z]{13}$

but its not working.

I need to create a Regular Expression for 13 characters alphanumeric string having exactly 3 characters and 10 numbers.

I am trying this:

^(?=.*\d{10})(?=.*[a-zA-Z]{3})[0-9a-zA-Z]{13}$

but its not working.

• javascript
• regex

Share Follow edited Apr 15, 2014 at 11:51 Rahil Wazir 10.1k1111 gold badges4545 silver badges6565 bronze badges asked Apr 15, 2014 at 11:33 user3535700user3535700 2311 silver badge33 bronze badges 7

• I am trying with ^(?=.*\d{10})(?=.*[a-zA-Z]{3})[0-9a-zA-Z]{13}$ but its not working. – user3535700 Commented Apr 15, 2014 at 11:45
• /^[a-zA-Z]{3}[0-9]{10}$/ – Batu.Khan Commented Apr 15, 2014 at 11:50
• 3 characters THEN 10 numbers, or ANY order? – FrostbiteXIII Commented Apr 15, 2014 at 11:57
• @BatuZet Thanks for helping but /^[a-zA-Z]{3}[0-9]{10}$/ checks for 3 characters followed by 10 numbers, whereas string can have 3 characters anywhere in it. – user3535700 Commented Apr 15, 2014 at 12:04
• @FrostbiteXIII No particular order. It can be abc0123456789 or 0abc123456789 or 0a1345b6789c i.e. it can be anything having exactly 3 characters and 10 numbers. – user3535700 Commented Apr 15, 2014 at 12:05

 |  Show 2 more ments

3 Answers 3

Sorted by: Reset to default 5

If order doesn't matter, I believe this should work:

/^(?=.{13}$)(\d*([A-Z]\d*){3})$/ig or /^(?=.{13}$)([0-9]*([a-zA-Z][0-9]*){3})$/g

This breaks down as follows:

• ^: Start of string
• (?=.{13}$): Look ahead expression - this looks ahead to find something (in this case 13 characters then the end of a string) before going on to do the actual RegEx
• \d*: Find any number of 0-9 (\d is equivalent to [0-9])
• ([A-Z]\d*){3}: Find one A-Z then any number of 0-9 (x3 to find your three alphas)
• $: End of string
• i: Ignore case
• g: Find global

Try this (with case insensitive and ^$ matches newline options set

(?=^[a-z0-9]{13}$)([a-z]*[0-9][a-z]*){10}

or

(?=^[a-z0-9]{13}$)([^0-9]*[0-9][^0-9]*){10}

Ensure only 13 characters in the string, and only letters or digits

Look for exactly 10 digits in the string

EDIT was to change from three digits to ten digits.

Regex Explanation

(?=^[a-z0-9]{13}$)(?:[^0-9]*[0-9][^0-9]*){10}

Options: Case insensitive; Exact spacing; Dot doesn't match line breaks; ^$ match at line breaks; Parentheses capture

Ensure line is exactly 13 characters, with only letters and digits

Assert that the regex below can be matched, starting at this position (positive lookahead) «(?=^[a-z0-9]{13}$)»
   Assert position at the beginning of a line (at beginning of the string or after a line break character) (line feed) «^»
   Match a single character present in the list below «[a-z0-9]{13}»
      Exactly 13 times «{13}»
      A character in the range between “a” and “z” (case insensitive) «a-z»
      A character in the range between “0” and “9” «0-9»
   Assert position at the end of a line (at the end of the string or before a line break character) (line feed) «$»

Ensure there are exactly ten digits in the line

Match the regular expression below «(?:[^0-9]*[0-9][^0-9]*){10}»
   Exactly 10 times «{10}»
   Match any single character NOT in the range between “0” and “9” «[^0-9]*»
      Between zero and unlimited times, as many times as possible, giving back as needed (greedy) «*»
   Match a single character in the range between “0” and “9” «[0-9]»
   Match any single character NOT in the range between “0” and “9” «[^0-9]*»
      Between zero and unlimited times, as many times as possible, giving back as needed (greedy) «*»

Created with RegexBuddy

This is inelegant, but it works for all my tests:

/^(?=[\da-zA-Z]{13}$)(?=([^a-zA-Z]*[a-zA-Z]){3})(?!([^a-zA-Z]*[a-zA-Z]){4})(?=(\D*\d){10})(?!(\D*\d){11}).*$/

Just ask if it works for you and you want an explanation, or else please provide a test case where it does not work correctly