(PHP 4, PHP 5)
strpos — Find position of first occurrence of a string
Returns the numeric position of the first occurrence of needle in the haystack string. Unlike the strrpos() before PHP 5, this function can take a full string as the needle parameter and the entire string will be used.
The string to search in
If needle is not a string, it is converted to an integer and applied as the ordinal value of a character.
The optional offset parameter allows you to specify which character in haystack to start searching. The position returned is still relative to the beginning of haystack.
Returns the position as an integer. If needle is not found, strpos() will return boolean FALSE.
Ta funkcja może zwrócić Boolean FALSE, ale może też zwrócić wartość innego typu niż Boolean, która oznacza wartość FALSE, takie jak 0 lub "". Aby uzyskać więcej informacji proszę zapoznać się z rozdziałem Typy logiczne. Można używać operatora === do testowania zwracanych wartości przez tę funkcję.
Przykład #1 Using ===
<?php
$mystring = 'abc';
$findme = 'a';
$pos = strpos($mystring, $findme);
// Note our use of ===. Simply == would not work as expected
// because the position of 'a' was the 0th (first) character.
if ($pos === false) {
echo "The string '$findme' was not found in the string '$mystring'";
} else {
echo "The string '$findme' was found in the string '$mystring'";
echo " and exists at position $pos";
}
?>
Przykład #2 Using !==
<?php
$mystring = 'abc';
$findme = 'a';
$pos = strpos($mystring, $findme);
// The !== operator can also be used. Using != would not work as expected
// because the position of 'a' is 0. The statement (0 != false) evaluates
// to false.
if ($pos !== false) {
echo "The string '$findme' was found in the string '$mystring'";
echo " and exists at position $pos";
} else {
echo "The string '$findme' was not found in the string '$mystring'";
}
?>
Przykład #3 Using an offset
<?php
// We can search for the character, ignoring anything before the offset
$newstring = 'abcdef abcdef';
$pos = strpos($newstring, 'a', 1); // $pos = 7, not 0
?>
Informacja: Ta funkcja jest bezpieczna dla danych binarnych.