strncasecmp
I ran the following experiment to compare arrays.
1 st - using (substr($key,0,5 == "HTTP_") & 2 nd - using (!strncmp($key, 'HTTP_', 5))
I wanted to work out the fastest way to get the first few characters from a array
BENCHMARK ITERATION RESULT IS:
if (substr($key,0,5 == "HTTP_").... - 0,000481s
if (!strncmp($key, 'HTTP_', 5)).... - 0,000405s
strncmp() is 20% faster than substr() :D
<?php
// SAMPLE FUNCTION
function strncmp_match($arr)
{
foreach ($arr as $key => $val)
{
//if (substr($key,0,5 == "HTTP_")
if (!strncmp($key, 'HTTP_', 5))
{
$out[$key] = $val;
}
}
return $out;
}
// EXAMPLE USE
?><pre><?php
print_r(strncmp_match($_SERVER));
?></pre>
will display code like this:
Array
(
[HTTP_ACCEPT] => XXX
[HTTP_ACCEPT_LANGUAGE] => pl
[HTTP_UA_CPU] => x64
[HTTP_ACCEPT_ENCODING] => gzip, deflate
[HTTP_USER_AGENT] => Mozilla/4.0
(compatible; MSIE 7.0;
Windows NT 5.1;
.NET CLR 1.1.4322;
.NET CLR 2.0.50727)
[HTTP_HOST] => XXX.XXX.XXX.XXX
[HTTP_CONNECTION] => Keep-Alive
[HTTP_COOKIE] => __utma=XX;__utmz=XX.utmccn=(direct)|utmcsr=(direct)|utmcmd=(none)
)
strncmp
(PHP 4, PHP 5)
strncmp — 처음 n 문자의 이진 호환 문자열 비교
설명
int strncmp
( string $str1
, string $str2
, int $len
)
이 함수는 비교에 사용하는 각각의 문자열에서 (길이를 제한하는) 문자 수(len )를 지정할 수 있는 차이를 제외하면, strcmp()와 동일합니다.
str1 이 str2 보다 작으면 < 0을; str1 이 str2 보다 크면 > 0을, 같으면 0을 반환합니다.
이 비교가 대소문자를 구별하는 점에 주의하십시오.
참고: ereg(), strncasecmp(), strcasecmp(), substr(), stristr(), strcmp(), strstr().
add a note
User Contributed Notesstrncmp
codeguru at crazyprogrammer dot cba dot pl
24-Jan-2008 11:07
24-Jan-2008 11:07
Anonymous
17-Apr-2002 04:46
17-Apr-2002 04:46
strncmp("sample","sam",4) returns 1 because the final requirement is if one string terminates before len, then the other must also terminate at that position.
You can imagine that all your strings have one more final, invisible "termination" character. If that termination character happens to be within in len, then it must match, too.
For instance, write that termination character with, say, the sequence "\0". Then you can equivalently consider that function call as strncmp("sample\0","sam\0",4).
So, the "p" in "sample" does not match the termination character in "sam".