Learn PHP programming

strcmp – String Compare

PHP HELP — Tue, 18 Aug 2009 11:51:59 +0000

Here are some of string comparation php functions:

strcmp($s1, $s2) – returns 0 if $s1 and $s2 are equal, a negativ value (-1) if $s1<$s2 and positive value (1) if $s1>$s2. The string comparation is case-sensitive, character by character, comparing character’s codes. Uppercase chars are considered smaller than minuscule chars. Numbers are considered smaller than letters.
strcasecmp($s1, $s2) – idem, but the string compare is case-insensitive
strncmp($s1, $s2, $nr) – like strcmp() but it compare only the first $nr chars of the 2 strings.
strncasecmp($s1, $s2, $nr) – idem, case-insensitive
strnatcmp($s1, $s2) – natural comparation, case-sensitive of the 2 strings (like natsort())
strnatcasecmp($s1, $s2) – idem, but case-insensitive

String compare function examples

$s1 = "1 Euro";
$s2 = "2 Euro";
$s3 = "10 Euro";
$s4 = "10 euro";
echo strcmp($s1, $s2); // -1 ($s1 is alphabetically before $s2)
echo strcmp($s3, $s4); // -1 (the code of E char is before e char)
echo strcasecmp($s3, $s4); // 0 (case insensitive, the two strings are equal)
echo strcmp($s2, $s3); // 1 (char 1 is before 2)
echo strnatcmp($s2, $s3); // -1 (char 2 as number is before 10)
echo strncmp($s1, $s4, 1); // 0 (comparing only the first char, there is equality)
?>

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strpos – Find the Position of a String

PHP HELP — Tue, 18 Aug 2009 11:03:21 +0000

Finding the position of a string or substring can be made with this php functions:

strpos($string, $seached_string [,$offset]) – returns position of the first occurrence of $searched_string inside $string or FALSE if $searched_string is not found. If $offset is specified, the seach will be made starting with $offset position.
stripos($string, $seached_string [,$offset]) – idem, but the search is case-insensitive
strrpos($string, $seached_string [,$offset]) – returns the position of the last occurrence of $searched_string inside $string, or FALSE
strripos($string, $seached_string [,$offset]) – idem with strrpos but is case-insensitive

Finding the position of a substring in string examples

$string = "Count of Monte Cristo";
echo strpos($string, "nt"); // 3 (first occurrence of nt inside $string)
echo strrpos($string, "nt"); // 11 (last occurrence of nt)
echo strpos($string, "nt", 4); // 11 (first occurrence of nt after 4-th position)
var_dump(strpos($string, "count")); // FALSE, because strpos() is case-sensitive
echo stripos($string, "Count"); //0
?>

Be careful when you verify the result of those php functions! When the searched string is at the begining of the string in which we are searching, the strpos() function returns 0, which is == FALSE; so if we use the == operator there is the risk to get wrong conclusions:

$string = "Count of Monte Cristo";
if(strpos($string, "Co") == false) { // "Co" is at position 0, which == false!
echo "It hasn't been found"; // this line will execute!
}
?>

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PHP sef url function

PHP HELP — Wed, 22 Jul 2009 11:48:24 +0000

This is another PHP sef function, much better to use in case you want to get remove characters that are not a-z, 0-9, dash, underscore or space, then remove all leading and trailing spaces, change all dashes, underscores and spaces to dashes and return the modified string in lower case.

PHP search engine friendly url function

function sef($string)
{
// remove all characters that aren’t a-z, 0-9, dash, underscore or space
$not_acceptable_characters = '#[^-a-zA-Z0-9_ ]#';
$string = preg_replace($not_acceptable_characters, '', $string);
// remove all leading and trailing spaces
$string = trim($string);
// change all dashes, underscores and spaces to dashes
$string = preg_replace('#[-_ ]+#', '-', $string);
// return the modified string
return strtolower($string);
}

PHP SEF Clean url function

php echo and print differences

PHP HELP — Wed, 27 May 2009 09:56:32 +0000

There are some differences between echo and print in php, echo and print are not functions.
First, you can pass more than one parameter to echo, print doesn’t allow more than one parameter.
Example:

$a = 5;
$b = 6;
echo $a; // will output 5
echo $a, $6; // outputs 56
print $a; //will output 5
print $a, $b; // error, print doesn't allow more than one parameter
?>

Now, let’s see something interesting…

$a = 5;
echo " \$a is:" . print $a; // will output 5 $a is 1
?>

First, you use \ (backslash) character to treat $a as a string not variable. Then, this is important, the code will be executed in this manner: first is executed print then echo. You may ask but why it will output “1″… Let’s see the next example:
Remember that print($arg) will return 1!

$a = 5;
echo (print($a)); // will output 51
?>

As you can see, it will output 51 because php print is executed first (5) and with echo returns 1.

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