I am writing some regex on a php form to validate input and have come up with this, for example -
if (empty($first) || !eregi("^[A-Za-z]+[- ]?[A-Za-z]+$", $first))
for checking a persons name. This allows a single name, or a hyphenated double name, or a non-hyphenated double name, and it works. My question is this - why is the third set followed by a '+' optional? I thought the + meant the preceding group is present 1 or more times. The ? means the preceding group is present 0 or more times. Why is it that when I put a ? in the place of the + after the last ]
if (empty($first) || !eregi("^[A-Za-z]+[- ]?[A-Za-z]?$", $first))
the regex is broken?
The ? doesn't mean 0 or more, it means 'optional' - 0 or 1 times.
without specific examples on what works or what breaks, I can't explain it much better than this - but rest assured, that's your problem.
now I'm sitting here wondering if ?* and ?+ are interchangeable, and thinking so.
Cheers,
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- Martin Norland, Sys Admin / Database / Web Developer, International Outreach x3257
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