PHP String Parsing Substring
Example
Substring returns the portion of string specified by the start and length parameters.
var_dump(substr("Boo", 1)); // string(2) "oo"
If there is a possibility of meeting multi-byte character strings, then it would be safer to use mb_substr.
$cake = "cakeæøå";
var_dump(substr($cake, 0, 5)); // string(5) "cake�"
var_dump(mb_substr($cake, 0, 5, 'UTF-8')); // string(6) "cakeæ"
Another variant is the substr_replace function, which replaces text within a portion of a string.
var_dump(substr_replace("Boo", "0", 1, 1)); // string(3) "B0o"
var_dump(substr_Replace("Boo", "ts", strlen("Boo"))); // string(5) "Boots"
Let's say you want to find a specific word in a string - and don't want to use Regex.
$hi = "Hello World!";
$bye = "Goodbye cruel World!";
var_dump(strpos($hi, " ")); // int(5)
var_dump(strpos($bye, " ")); // int(7)
var_dump(substr($hi, 0, strpos($hi, " "))); // string(5) "Hello"
var_dump(substr($bye, -1 * (strlen($bye) - strpos($bye, " ")))); // string(13) " cruel World!"
// If the casing in the text is not important, then using strtolower helps to compare strings
var_dump(substr($hi, 0, strpos($hi, " ")) == 'hello'); // bool(false)
var_dump(strtolower(substr($hi, 0, strpos($hi, " "))) == 'hello'); // bool(true)
Another option is a very basic parsing of an email.
$email = "[email protected]";
$wrong = "foobar.co.uk";
$notld = "foo@bar";
$at = strpos($email, "@"); // int(4)
$wat = strpos($wrong, "@"); // bool(false)
$nat = strpos($notld , "@"); // int(3)
$domain = substr($email, $at + 1); // string(11) "example.com"
$womain = substr($wrong, $wat + 1); // string(11) "oobar.co.uk"
$nomain = substr($notld, $nat + 1); // string(3) "bar"
$dot = strpos($domain, "."); // int(7)
$wot = strpos($womain, "."); // int(5)
$not = strpos($nomain, "."); // bool(false)
$tld = substr($domain, $dot + 1); // string(3) "com"
$wld = substr($womain, $wot + 1); // string(5) "co.uk"
$nld = substr($nomain , $not + 1); // string(2) "ar"
// string(25) "[email protected] is valid"
if ($at && $dot) var_dump("$email is valid");
else var_dump("$email is invalid");
// string(21) "foobar.com is invalid"
if ($wat && $wot) var_dump("$wrong is valid");
else var_dump("$wrong is invalid");
// string(18) "foo@bar is invalid"
if ($nat && $not) var_dump("$notld is valid");
else var_dump("$notld is invalid");
// string(27) "foobar.co.uk is an UK email"
if ($tld == "co.uk") var_dump("$email is a UK address");
if ($wld == "co.uk") var_dump("$wrong is a UK address");
if ($nld == "co.uk") var_dump("$notld is a UK address");
Or even putting the "Continue reading" or "..." at the end of a blurb
$blurb = "Lorem ipsum dolor sit amet";
$limit = 20;
var_dump(substr($blurb, 0, $limit - 3) . '...'); // string(20) "Lorem ipsum dolor..."
