Extracting Data from Text Files

Question

There appear to be similar questions to this in other languages but I can\'t find one in R.

I have a number of text files in the subdirectories of a directory; they

Answer 1

maybe

library(stringr)
f <- readLines("datafile.txt")
cline <- grep("NUMBER OF CARTESIAN GAUSSIAN BASIS FUNCTIONS",f,
                    value=TRUE)
val <- as.numeric(str_extract(cline,"[0-9]+$"))

will work?

To get the other values, try

cline <- grep("^ +CPU timing information",f)
(numstr <- sapply(str_extract_all(f[cline+2:5],"[0-9.]+"),as.numeric))
##         [,1]     [,2]     [,3]     [,4]
## [1,]    0.000    1.000    2.000    3.000
## [2,] 8853.469 8850.817 8851.925 8847.992
## [3,]  133.948  126.587  128.576  125.871
## [4,] 8987.417 8977.405 8980.501 8973.864

The sapply has transposed the matrix of values, so the last row is the bit we want (corresponds to the last column in the file). Extract it using numstr[4,] or numstr[nrow(numstr),] or tail(numstr,1).

(edit: allow spaces before the "CPU timing" string) (edit: do it right!)

(To do this for all the log files, package it in a function and use list.files(pattern="\\.log$") in combination with sapply ...)