[R-sig-Geo] Helping with write a function. Merging shape file with all fields?

[Zia Ahmed]

Hi Matt:
With help of Jim Holtman  (my R Guru!), I am able to modified your code 
for selecting  particular type  of shape  files from  different folders 
and able to  combine them together. Thank you so much!
However, final polygon does not contain any filed  (suppose county name, 
FIPS code  etc) of  the shape files those I used for merging . How do I 
keep these fields  in  my final polygon.   Any idea?
Thanks
Zia

# Rode for combing Code
library(rgdal)
setwd("D:/test")
files <- list.files(pattern="soilmu_a_ny.*.shp$", 
recursive=TRUE,full.names=TRUE)

# Get polygons from first file

data.first <- readOGR(files[1],gsub("^.*/(.*).shp$", "\\1", files[1]))
polygons <- slot(data.first, "polygons")

# add polygons from remaining files

for (i in 2:length(files)) {
    data.temp <- readOGR(files[i], gsub("^.*/(.*).shp$", "\\1",files[i]))
    polygons <- c(slot(data.temp, "polygons"),polygons)
    }

# rename IDs of Polygons

for (i in 1:length(polygons)) {
slot(polygons[[i]], "ID") <- paste(i)
    }

# ain't that spatial

spatialPolygons <- SpatialPolygons(polygons)
spdf <- SpatialPolygonsDataFrame(spatialPolygons,
data.frame(NewID =1:length(polygons)))

# output combined results
plot(spatialPolygons)
writeOGR(spdf, dsn="C:/test/combined.shp", layer="combined", 
driver="ESRI Shapefile")