PHP removes the null value in the array. foreach ($ arras $ k & gt; $ v) {if (! $ V) unset ($ arr [$ k]);} I was surprised to see that someone was prompted to use array_filter when I was hanging out on the Internet. I opened the manual and looked at it. I found that I had been keeping a guard of Baoshan, but I didn't know how to use it. Arra PHP removes null values from the array
foreach( $arr as $k=>$v){ if( !$v ) unset( $arr[$k] ); }
Well, it used to be beautiful.
When hanging out on the Internet, I was surprised to see a prompt using array_filter. I opened the manual and looked at it. I found that I had been keeping a guard of Baoshan, but I didn't know how to use it.
The array_filter function uses the callback function to filter the array. it is always thought that the callback function can be used for processing, but it is not found that there is another sentence in the manual. if there is no callback function, by default, items whose values are false are deleted.
Routine:
$entry = array( 0 => 'foo', 1 => false, 2 => -1, 3 => null, 4 => '' ); print_r(array_filter($entry));
Array ( [0] => foo [2] => -1 )
In the future, I still need to read more manuals ......
Like array_slice, it is also a good thing. Unfortunately, I have never paid attention to it before.
Suggestion: The most important two chapters in PHP should be array operations and string operations. the functions in these two chapters must be skillful. you can check other functions when using them.
