有人可以解释下面给出的代码吗？

Question

$array_words is an array which has every 'single' word from a file in it.

---

$array_2_words = implode(" ", $array_words);

$array_2_words = preg_replace("/[^A-Z0-9-\' ]/i", "", $array_2_words);

$array_2_words = str_replace("  ","",$array_2_words);

$jk = explode(" ",$array_2_words);

$i = sizeof($jk);
$j = 0;

$array_2_words="";

for($j=0;$j<$i-1;$j++)
{
    $array_2_words[] = $jk[$j]." ".$jk[$j+1];
}

I know what the result of this code is, making an array with 2 words each. For example: It will make from a sentence like this: This is a test sentence the following array:

This is is a a test test sentence

But would someone be so kind to comment (each|some) line(s) to how it exactly does this from an array with 1 word in every entry to 2 words like my example.

I could just leave this code in my script but I will only fool myself by not knowing how it works.

Thanks in advance!

Answer 1

The magic happens only on the last line.

$array_2_words[] = $jk[$j]." ".$jk[$j+1];

This line means: Take an array of words ($jk) and combine word n and word n+1 from the array of words and push them into $array_2_words.

so what happens is:

$jk[0]." ".$jk[1] = "This" + " " + "is" = "This is"
$jk[1]." ".$jk[2] = "is" + " " + "a" = "is a"
$jk[2]." ".$jk[3] = "a" + " " + "test" = "a test"