我如何编写两个函数,如果它以指定的字符/字符串开头或以指定的字符串结尾,那么它们将接受字符串并返回?
例如:
$str = '|apples}';
echo startsWith($str, '|'); //Returns true
echo endsWith($str, '}'); //Returns true
我如何编写两个函数,如果它以指定的字符/字符串开头或以指定的字符串结尾,那么它们将接受字符串并返回?
例如:
$str = '|apples}';
echo startsWith($str, '|'); //Returns true
echo endsWith($str, '}'); //Returns true
当前回答
我会这样做
function startWith($haystack,$needle){
if(substr($haystack,0, strlen($needle))===$needle)
return true;
}
function endWith($haystack,$needle){
if(substr($haystack, -strlen($needle))===$needle)
return true;
}
其他回答
如果速度对你很重要,试试这个。(我认为这是最快的方法)
仅适用于字符串,如果$haystack只有1个字符
function startsWithChar($needle, $haystack)
{
return ($needle === $haystack[0]);
}
function endsWithChar($needle, $haystack)
{
return ($needle === $haystack[strlen($haystack) - 1]);
}
$str='|apples}';
echo startsWithChar('|',$str); //Returns true
echo endsWithChar('}',$str); //Returns true
echo startsWithChar('=',$str); //Returns false
echo endsWithChar('#',$str); //Returns false
$ends_with = strrchr($text, '.'); // Ends with dot
$start_with = (0 === strpos($text, '.')); // Starts with dot
function startsWith($haystack, $needle, $case = true) {
if ($case) {
return (strcmp(substr($haystack, 0, strlen($needle)), $needle) === 0);
}
return (strcasecmp(substr($haystack, 0, strlen($needle)), $needle) === 0);
}
function endsWith($haystack, $needle, $case = true) {
if ($case) {
return (strcmp(substr($haystack, strlen($haystack) - strlen($needle)), $needle) === 0);
}
return (strcasecmp(substr($haystack, strlen($haystack) - strlen($needle)), $needle) === 0);
}
贷方:
检查字符串是否以另一个字符串结尾
检查字符串是否以另一个字符串开头
我意识到这已经完成,但您可能需要查看strncmp,因为它允许您将字符串的长度与之进行比较,因此:
function startsWith($haystack, $needle, $case=true) {
if ($case)
return strncasecmp($haystack, $needle, strlen($needle)) == 0;
else
return strncmp($haystack, $needle, strlen($needle)) == 0;
}
上面的正则表达式函数,但上面还建议了其他调整:
function startsWith($needle, $haystack) {
return preg_match('/^' . preg_quote($needle, '/') . '/', $haystack);
}
function endsWith($needle, $haystack) {
return preg_match('/' . preg_quote($needle, '/') . '$/', $haystack);
}