regular expressions

[tompat]

I am trying to learn regular expressions and have a question for the following codes

Why does this code allow everything
return (preg_match_all ("/[a-z]\'*\-*\s*/", $testString));

Why does this allow nothing
return (preg_match_all ("/^[a-z]\'*\-*\s*$/", $testString));

[cpradio]

What test strings are you using?

The difference between the two is quite simple, the latter requires the beginning of the string to match a-z (lowercase) and end with at least 1 space.

[tompat]

Then what do I do to make the 1st code only allow whats listed?

[cpradio]

Tell me what strings you want captured and what you do not want captured and I can answer that.

[tompat]

That is for first and last name, I want to allow for spaces, hyphens and apostrophes. Maybe you clarify my assumptions about regular expressions. Does it return 0 when a character is inserted that is not in the argument or does it just check to see if the listed characters are there?

[ScallioXTX]

The difference between the two is quite simple, the latter requires the beginning of the string to match a-z (lowercase) and end with at least 0 spaces.

There, fixed that for you

[ScallioXTX]

That is for first and last name, I want to allow for spaces, hyphens and apostrophes.

I think what you're looking for this

~^[a-zA-Z'\s-]+$~

Please note that this does not allow for special characters like the é in my name.
For names I mostly find it easiest to just strip_tags to prevent script injection and be done with it.