Iterate several operations over several files, lapply?

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RRR
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Iterate several operations over several files, lapply?

RRR
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I am new to R and would like to read in a list of files as separate data frames, perform several operations on each, and save them out as separate files with dynamic file names. I am thinking I should use lappy, but not sure.

Here is the code I wrote that works for one file:

df <- read.fwf('USC00011084.dly', widths = c(21, rep(c(5, 1, 1, 1),31)))

df2 <- df[-c(3:5, 7:9, 11:13, 15:17, 19:21, 23:25, 27:29, 31:33, 35:37, 39:41, 43:45, 47:49, 51:53, 55:57, 59:61, 63:65, 67:69, 71:73, 75:77, 79:81, 83:85, 87:89, 91:93, 95:97, 99:101, 103:105, 107:109, 111:113, 115:117, 119:121, 123:125)]

df2[df2=="-9999"]<-NA

df$new <- rowSums(df2[,2:32], na.rm = TRUE)

df2["Total"] <- df$new

colnames(df2) <- c("StationDateType", "1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12", "13", "14", "15", "16", "17", "18", "19", "20", "21", "22", "23", "24", "25", "26", "27", "28", "28", "30", "31", "TotalMonthly")

Prcp <- df2[grep("PRCP", df2$StationDateType),]

write.table(Prcp, "USC00011084Prcp.txt", sep="\t", row.names=FALSE)

How can I do this for a list of files in a directory? Any ideas? Thank you.
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