startsWith() and endsWith() functions in PHP
How can I write two functions that would take a string and return if it starts with the specified character/string or ends with it?
For example:
$str = '|apples}';
echo startsWith($str, '|'); //Returns true
echo endsWith($str, '}'); //Returns true
PHP
- asked 8 years ago
- B Butts
2Answer
<?php
function startsWith($haystack, $needle)
{
return strncmp($haystack, $needle, strlen($needle)) === 0;
}
function endsWith($haystack, $needle)
{
return $needle === '' || substr_compare($haystack, $needle, -strlen($needle)) === 0;
}
- answered 8 years ago
- Gul Hafiz
It is possible to use strrpos and strpos to check start-with and ends-with respectively:
function startsWith($haystack, $needle) {
// search backwards starting from haystack length characters from the end
return $needle === "" || strrpos($haystack, $needle, -strlen($haystack)) !== false;
}
function endsWith($haystack, $needle) {
// search forward starting from end minus needle length characters
return $needle === "" || (($temp = strlen($haystack) - strlen($needle)) >= 0 && strpos($haystack, $needle, $temp) !== false);
}
Tests and results (compare with this):
startsWith("abcdef", "ab") -> true
startsWith("abcdef", "cd") -> false
startsWith("abcdef", "ef") -> false
startsWith("abcdef", "") -> true
startsWith("", "abcdef") -> false
endsWith("abcdef", "ab") -> false
endsWith("abcdef", "cd") -> false
endsWith("abcdef", "ef") -> true
endsWith("abcdef", "") -> true
endsWith("", "abcdef") -> false
Note: the strncmp and substr_compare functions will outperform this function.
- answered 8 years ago
- G John
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