Question

I need to verify a credit card (dummy – i’m not doing any transaction in real). The conditions are

1. It has to be between 10 and 16 digits.

2. Start with a digit 3 or 4

3. Only digits are allowed i mean [0-9].

I tried it and mine was [3-4][0-9]{10-16}. But it seems to be not yielding results.

Thank you in anticipation

Answer 1

Should be:

^[34][0-9]{9,15}$

• Start and end anchors are important, or the regex might match only a part from the whole string (for example. 16 digits out of 20)
• [34] one of the characters. [3-4] is the same.
• {9,15} is the proper syntax. Note that [34] is the first digit, so you need to subtract one.

Some Examples: http://www.rubular.com/r/q61cPPYW7E