lua: pattern matching and extracting a phone number

Question

I am having trouble crafting a function that has the following requirements in Lua:

• Takes a string phone_number and 2-digit country_code as input.
• phone_number has the form {1 || ""}{country_code}{10 or 11-digit mobile number}

I need as output the 10 or 11-digit mobile number.

Example I/O:

phone_number= "552234332344", country_code= "55" => "2234332344"

phone_number= "15522343323443", country_code= "55" => "22343323443"

Thanks!

Answer 1

Try "(1?)(%d%d)(%d+)". Using this with your examples:

print(("15522343323443"):match("(1?)(%d%d)(%d+)"))
print(("5522343323443"):match("(1?)(%d%d)(%d+)"))

will print:

1   55  22343323443
55  22343323443

If you need exactly 10 or 11 digits in the phone number, then specify %d 10 times and then add %d?. %d is a character class that matches any number and question mark modifier matches the previous character or a character class 0 or 1 time.

Answer 2

Try this

^[0-9]{1,3}\s\|{2}\s[0-9]{10,11}$

This expression is for pattern like 1 || 9945397865 like you asked i guess . .

EDITED: I guess this works

• fetch string length using string.len('552234332344') => Output: 12
• match string using string.match ('552234332344', ^%d) => Output: 552234332344 if matches
• fetch country code using string.sub ('552234332344', 1, 2) => Output: 55
• fetch phone no. using string.sub('552234332344', 3) => Output: 2234332344