[R-sig-Geo] R Help

[Esu Esu]

Dear All,
I am new to R-programming. I have question if anyone can help me with:Q: how can I create functions in R to compute the area (A), centroid (Cx and Cy) and perimeter (P) of a polygon list .  I want to write R functions to compute these quantities for individual polygons, as well asan overall function to take a polygon list and return a data frame with four columns and the samenumber of rows as polygons in the list.  Each quantity should correspond to each column. it is (sp) class object. 
Hope to find any suggestion or answer 
 RegardsMuhsien 
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