从数组中删除空值和空格值（不是array_filter）

I seem to be hitting a wall when it comes to removing empty values in my array.

I have the following array:

key:0 value: 

key:1 value:type

key:3 value:gear

key:4 value: 

key:5 value:rarity

As you can see, Key 0, and Key 4 are both empty (or filled with a space).

I have tried the following, but it doesn't appear to have worked:

foreach($array as $key=>$value){
    if ($value == ' ' || $value=='' || $value==' ' || empty($value)) { unset($array[$key]); }
    echo 'key:'.$key.' value:'.$value.'</br></br>';
}

and even tried it in 2 foreach loops just to be sure, but still nothing.

There are two issues: First you're not calling continue even if you unset the array key, meaning that you still print the value. Second - you can easily use trim to remove any whitespace that would fubar the comparison.

foreach ($array as $key => $value) {
    if (empty($value) || !trim($value)) {
        unset($array[$key]);
        continue;
    }

    echo 'key:' . $key . ' value:' . $value . '</br></br>';
}

Let's not just rush to the "just do this" answer. Here is what you tried:

Code: (Demo)

$array=[0=>'',1=>'type',3=>'gear',4=>' ',5=>'rarity'];
foreach($array as $key=>$value){
    if ($value == ' ' || $value=='' || $value==' ' || empty($value)) { unset($array[$key]); }
    echo 'key:'.$key.' value:'.$value."
";
}
foreach($array as $key=>$value){
    if ($value == ' ' || $value=='' || $value==' ' || empty($value)) { unset($array[$key]); }
    echo 'key:'.$key.' value:'.$value."
";
}

It is doing what you asked it to do. The first loop unsets the unwanted elements AND prints the keys & values assigned to the "copy" of $array that foreach() "writes" & iterates. The second loop writes & iterates a new "copy" of $array (which was previously modified by the first loop) and you can see that the empty-ish elements are now gone.

Output:

key:0 value:        # unset $array[$key] and display $value (these are different entities
key:1 value:type
key:3 value:gear
key:4 value: 
key:5 value:rarity
key:1 value:type    # you see elements [0] and [4] are removed as intended
key:3 value:gear
key:5 value:rarity

Now, for the "Do this" part... You have several options. Here are a few:

Code: (Demo)

$array=[0=>'',1=>'type',3=>'gear',4=>' ',5=>'rarity'];

var_export(array_filter($array,function($v){return strlen(trim($v));}));  // professional grade: uses the function specifically designed to perform this function and the process will be instantly understood by future devs that read your code

var_export(preg_grep('/\S/',$array));  // A regular expression filter. Regex solutions should only be used when other methods will not suffice.  For this reason, this method is ill-advised

var_export(preg_grep('/^\s*$/',$array,PREG_GREP_INVERT));  // A regular expression filter (inverted pattern filteration). Regex solutions should only be used when other methods will not suffice.  For this reason, this method is ill-advised

foreach($array as $k=>$v){                    // possibly the fastest method, I didn't test, but it is also the most verbose and less descriptive as a technique
    if(!strlen(trim($v))){unset($array[$k]);}
}
var_export($array);

Output:

array (
  1 => 'type',
  3 => 'gear',
  5 => 'rarity',
)array (
  1 => 'type',
  3 => 'gear',
  5 => 'rarity',
)array (
  1 => 'type',
  3 => 'gear',
  5 => 'rarity',
)array (
  1 => 'type',
  3 => 'gear',
  5 => 'rarity',
)

Now the most important piece of advice to give you from the manual:

Returns FALSE if var exists and has a non-empty, non-zero value. Otherwise returns TRUE.
The following things are considered to be empty:
"" (an empty string)
0 (0 as an integer)
0.0 (0 as a float)
"0" (0 as a string)
NULL
FALSE
array()
(an empty array)
$var; (a variable declared, but without a value)

This "greedy" default behavior is used by empty() and array_filter() and can really throw a wrench into your task if you are unaware. This is why in my suggested methods, I write a custom filter condition and in the foreach loop, I replace empty() with a strlen() call.