package main
import (
"regexp"
"fmt"
)
func main() {
var re = regexp.MustCompile(`(?m)\b(34[0-9]{2}[ -])([0-9]{6}[ -])[0-9]{5}\b|\b34[0-9]{13}\b|\b(37[0-9]{2}[ -])([0-9]{6}[ -])[0-9]{5}\b|\b37[0-9]{13}\b`)
var str = `American Express
Requirements: American Express cards start with the number 34 or 37 and have 15 digits. Pattern is 4-6-5 when having spaces or dashes.
Pattern Parts:
Starts with number 34 and 15 length:
1) \b(34[0-9]{2}[ -])([0-9]{6}[ -])[0-9]{5}\b|\b34[0-9]{13}\b
Starts with number 37 and 15 length:
2) \b(37[0-9]{2}[ -])([0-9]{6}[ -])[0-9]{5}\b|\b37[0-9]{13}\b
Combining 1-2 to form one pattern:
\b(34[0-9]{2}[ -])([0-9]{6}[ -])[0-9]{5}\b|\b34[0-9]{13}\b|\b(37[0-9]{2}[ -])([0-9]{6}[ -])[0-9]{5}\b|\b37[0-9]{13}\b
Test Cases:
Positive (Should fire):
15 length, no space, start with 34 342312341234112
15 length, dashes, start with 34 3423-123456-12345
15 length, spaces, start with 34 3423 123456 12345
15 length, no space, start with 37 372112341234123
15 length, dashes, start with 37 3721-123456-12345
15 length, spaces, start with 37 3721 123456 12345
Embedded in sentence with space:
15 length, no space, start with 34 Here is the cc: 342312341234112
15 length, dashes, start with 34 Here is the cc: 3423-123456-12345
15 length, spaces, start with 34 Here is the cc: 3423 123456 12345
15 length, no space, start with 37 Here is the cc: 372112341234123
15 length, dashes, start with 37 Here is the cc: 3721-123456-12345
15 length, spaces, start with 37 Here is the cc: 3721 123456 12345
15 length, no space, start with 34 Credit Card#:342312341234112
15 length, dashes, start with 34 Credit Card#:3423-123456-12345
15 length, spaces, start with 34 Credit Card#:3423 123456 12345
15 length, no space, start with 37 Credit Card#:372112341234123
15 length, dashes, start with 37 Credit Card#:3721-123456-12345
15 length, spaces, start with 37 Credit Card#:3721 123456 12345
Negative (Should Not Fire):
15 length, no space, not start with 34 352312341234112
15 length, dashes, not start with 34 3523-123456-12345
15 length, spaces, not start with 34 3523 123456 12345
15 length, no space, not start with 37 362112341234123
15 length, dashes, not start with 37 3621-123456-12345
15 length, spaces, not start with 37 3621 123456 12345
15 length, no space, start with 34, embedded Credit Card Number342312341234112
15 length, dashes, start with 34, malformed 3423-1234-1234-112
15 length num matching pattern but embedded User ID: 000000342312341234112000000`
for i, match := range re.FindAllString(str, -1) {
fmt.Println(match, "found at index", i)
}
}
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Golang, please visit: https://golang.org/pkg/regexp/