xml - Getting last child in SimpleXMLElement Object with PHP -

again think i'm missing basic here, can't figure out.

i'm parsing xml file formatted excel, using simplexml in php.

my xml file looks following:

simplexmlelement object (   [documentproperties] => simplexmlelement object (      [author] => surname name      [lastauthor] => name surname      [created] => 2016-08-01t10:15:25z      [version] => 14.00 )   [officedocumentsettings] => simplexmlelement object ( [allowpng] => simplexmlelement object ( ) )   [excelworkbook] => simplexmlelement object ( [windowheight] => 9375 [windowwidth] => 9705 [windowtopx] => 270 [windowtopy] => 615 [protectstructure] => false [protectwindows] => false )   [styles] => simplexmlelement object ( [style] => simplexmlelement object ( [alignment] => simplexmlelement object ( ) [font] => simplexmlelement object ( ) ) )   [worksheet] => array (   [0] => simplexmlelement object (      [table] => simplexmlelement object (             [column] => array (                 [0] => simplexmlelement object ( )                  [1] => simplexmlelement object ( )                  [2] => simplexmlelement object ( ) )              [row] => array (                  [0] => simplexmlelement object (                      [cell] => array (                          [0] => simplexmlelement object ( [data] => model )                          [1] => simplexmlelement object ( [data] => qty )                          [2] => simplexmlelement object ( [data] => description )                          [3] => simplexmlelement object ( [data] => tags ) ) )                   [1] => simplexmlelement object (                     [cell] => array (                          [0] => simplexmlelement object ( [data] => model_name )                          [1] => simplexmlelement object ( [data] => 1 )                          [2] => simplexmlelement object ( [data] => item ) ) )   [....code repeats other rows/worksheets....] 

now, if want display author name, can like: echo $xml->documentproperties->lastauthor; , expected result. how display values in various rows/cells (keeping in mind xml files have diverse number of rows , rows not filled)?

i've tried following:

echo $xml->worksheet[0]->table->row[0]->cell[0]; 

but doing doesn't return value. able cycle through rows can display them html table.

any ideas?

thanks lot in advance help!