x <- "% latex table generated in R 2.15.1 by xtable 1.7-0 package\n% Thu Jul 26 17:49:09 2012\n\\begin{table}[ht]\n\\begin{center}\n\\begin{tabular}{rlllr}\n \\hline\ngrade & sex & disadvg & ethnicty & tlimth \\\\ \n \\hline\n 6 & M & YES & HISPANIC & 43 \\\\ \n 7 & M & NO & BLACK & 88 \\\\ \n 5 & F & YES & HISPANIC & 34 \\\\ \n 3 & M & YES & HISPANIC & 65 \\\\ \n 8 & M & YES & WHITE & 75 \\\\ \n \\hline\n\\end{tabular}\n\\end{center}\n\\end{table}\n"
cat(gsub("(?m)^(?:[^&]*&){1}\\s*([^&]*?)\\s*(?:&|\\\\)", "\\1XoX", x, perl = TRUE))
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