setwd("Put the path of your working folder here")
myfile1 <- list.files()
myfile2 <- lapply(myfile1, read.csv)
j <- 1
for (i in myfile2) {
	i$Distance <- ifelse(abs(i$Distance)>0.3, i$Distance, 0)
	write.csv(i, paste0(myfile1[j]))
	j <- j+1
}