PHP Using Strings

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Replacing substrings (replace certain parts of a document template; ex

<name> with client’s name etc)

mixed str_replace (mixed $needle, mixed $new_needle, mixed $haystack[, int $count] )

Replaces all instances of $needle in $haystack with $new_needleReturns a new string = a copy of $haystack with all replacements

made$count has to be a variable (lhs) that will be set to the number of

replacements made$needle, $new_needle, $haystack can be strings or arrays

Matching & replacing with string functions

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Feeback.htmlhttp://www.nku.edu/~frank/csc301/Examples/PHP_String

s/feedback.htmlhttp://www.nku.edu/~frank/csc301/Examples/PHP_String

s/processfeedback_v2_php.pdf

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The match function isint preg_match(string $pattern, string $str [, array &$matches [, …]])

1st argument is the pattern2nd argument is the subject stringReturns number of matches found:

1 (true) if there is a match – it stops at the first match found! 0 (false) otherwise

An optional 3rd argument will capture the actual matched string and the parenthesized subpatterns, if any.

int preg_match_all(…)Use to find all matches to the regular expression

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Regular Expressions

Character Classes[A-Z] uppercase letter[a-z] lowercase letter[0-9] digit

{5} exactly five{3,} three or more{1,4} one to four

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Metacharacters^ beginning of string$ end of string

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Regular ExpressionUsername – 5 to 10 lowercase letters?

$pattern = '/^[a-z]{5,10}$/';

if (!preg_match($pattern, $username))

{

echo "<p>$username is invalid.</p>";

}

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Regular ExpressionsSocial Security Number 123-45-6789

$pattern = '/^[0-9]{3}-[0-9]{2}-[0-9]{4}$/';

if (!preg_match($pattern, $ssn))

{

echo "<p>$ssn is invalid.</p>";

}

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Character classes\d any digit\D any non-digit\w Any letter, number, or underscore\W Anything that is not a letter, number, or underscore\s whitespace (space, tab, new line, etc.)\S An y non-whitespace

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Regular ExpressionsSocial Security Number 123-45-6789

$pattern = '/^\d{3}-\d{2}-\d{4}$/';

if (!preg_match($pattern, $ssn))

{

echo "<p>$ssn is invalid.</p>";

}

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Metacharacters[0-9]* * = zero or more[A-Z]+ + = one or more. . = match any character([A-Z]\. )? ? = either zero or one

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Regular ExpressionsLast name: Frank

$pattern = '/^[A-Z][a-z]+$/';

if (!preg_match($pattern, $last))

{

echo "<p>$last is invalid.</p>";

}

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Regular ExpressionsName: Charles Frank or Charles E. Frank

$pattern = '/^[A-Z][a-z]+ ([A-Z]\. )?[A-Z][a-z]+ $/';

if (!preg_match($pattern, $name))

{

echo "<p>$name is invalid.</p>";

}

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