php multidimensional array syntax -

The code below has two comment-out variations on one line, they produce different results, such as You will see that the individual letters of the key are mapped without having to place them between - $ arrays and [$ key] < P> Thanks!

  & lt ;? Php $ letters = array ('a', 'b', 'c'); $ Number = array (1,2,3); $ Matrix = array ('letter' = & gt; $ letters, 'number' = & gt; $ numbers); Forex currency ($ array => $ matrix in the form of a $) {echo ' 1;    
 
 
  "$ array [$ key]"  is defined as array access ( $ array [$ of] )  array $ array [$ of] ;; .  
  Similar to "$ array [$ key]"  interpreted as two different variables Done:  $ array  and  $ of .  similar to echo $ array. "[". $ Key ""] "; .