array_column unset
1,"pid"=>0,"views"=>100
],[
"uid"=>2,"pid"=>1,"views"=>200
],[
"uid"=>3,"views"=>300
],[
"uid"=>4,"views"=>400
],[
"uid"=>5,"pid"=>3,"views"=>500
]
);
//https://laravel-china.org/articles/16778
array_search('3',array_column($items,'uid'));// 2 uid =3所在的数据
unset($items[1]);
>>> $items
=> [
0 => [
"uid" => 1,"pid" => 0,"views" => 100,],2 => [
"uid" => 3,"views" => 300,3 => [
"uid" => 4,"views" => 400,4 => [
"uid" => 5,"pid" => 3,"views" => 500,]
>>> array_search(3,'uid'))
=> 1
>>> $r=array_combine(array_keys($items),'uid'));
=> [
0 => 1,2 => 3,3 => 4,4 => 5,$r)
=> 2斐波那契数列
return fibonacci_recursive($n - 1) + fibonacci_recursive($n - 2);}
for ($i = 1; $i <= 30; $i++) {
echo fibonacci_recursive($i) . " ";
}
耗时
3.52s user 0.00s system 99% cpu 3.521 total
function fibonacci_recursive_optimization($n) {
static $caches_arr = [];
if (isset($caches_arr[$n])) {
return $caches_arr[$n];
}
if ($n <= 1) {
$res = 1;
} else {
$res = fibonacci_recursive_optimization($n - 1) + fibonacci_recursive_optimization($n - 2);
}
$caches_arr[$n] = $res;
return $res;}
for ($i = 1; $i <= 30; $i++) {
echo fibonacci_recursive_optimization($i) . " ";
}
耗时
0.01s user 0.01s system 98% cpu 0.022 total
function fibonacci_closure() {
static $x = 0;
static $y = 1;
return function () use (&$x,&$y) {
[$x,$y] = [$y,$x + $y];
return $y;
};
}
$f = fibonacci_closure();
for ($i = 1; $i <= 30; $i++) {
echo $f() . " ";
}
耗时
0.02s user 0.01s system 99% cpu 0.030 total
Intervention/Image
text('测试写入中文',function($font) {
$font->file('foo/bar.ttf');
$font->size(24);
$font->color('#fdf6e3');
$font->align('center');
$font->valign('top');
$font->angle(45);
});
function to_unicode($string)
{
$str = mb_convert_encoding($string,'UCS-2','UTF-8');
$arrstr = str_split($str,2);
$unistr = '';
foreach ($arrstr as $n) {
$dec = hexdec(bin2hex($n));
$unistr .= '&#' . $dec . ';';
}
return $unistr;
}数据库查询中对 like 的值进行转义
where('title','like',"%".$keyword."%");https://laravel-china.org/topics/16945
function escape_like_str($str)
{
$like_escape_char = '!';
return str_replace([$like_escape_char,'%','_'],[
$like_escape_char.$like_escape_char,$like_escape_char.'%',$like_escape_char.'_',$str);
}
$query->where('title',"%".escape_like_str($keyword)."%");
