Ruby String Scanner

Scanning a string means remembering the position of a scan pointer which is just an index.

Ruby string scanner.

Advancing the scan pointer. Advances the scan pointer if advance pointer p otherwise not. Returns the matched string if return string p is true otherwise returns the number of bytes advanced. Ruby regular expressions ruby regex for short help you find specific patterns inside strings with the intent of extracting data for further processing two common use cases for regular expressions include validation parsing.

The point of scanning is to move forward a bit at a time so matches are sought after the scan pointer. Scans the string until the pattern is matched. There are other methods besides the plain scanners. Advances the scan pointer if advance pointer p otherwise not.

You can modify the string being scanned reset or terminate the scanner find out or change the position of the scan pointer skip ahead and so on. Scans the string until the pattern is matched. This method does affect the match register. Usually immediately after it.

You can look ahead in the string without actually scanning. This method does affect the match register. Given the string test string here are the pertinent scan pointer positions. In other words your program will be able to tell.

Think about an email address with a ruby regex you can define what a valid email address looks like.