Arrays and Hashes

Common Hash Functions: Each

• If you wish to iterate through an entire hash, you can use the values and keys functions, but a more elegant and efficient approach is to use the each(%Hashname) function.
• Every time each is called, the next succesive two element key and value pair is returned.
• When all values have been returned, each will return an empty list. This also resets the each operator to start back at the beginning of the hash for the next invocation.
• An assignment of a new value to the entire hash will reset the each function to the beginning of the hash. Adding or deleting elements to the hash within a loop that is iterating via each is at best confusing, and is likely to break something.
• Example:
  

  for ($aScalar=0; $aScalar < 10; $aScalar++) 
  { 
       $aHash{"Key$aScalar"} = "Value$aScalar"; 
  } 
  while ( ($Key, $Value) = each(%aHash) ) 
  { 
       print "Hash with Key=$Key is Value=$Value\n"; 
  } 
  

• Using each in a scalar context returns each successive key.