get.delim: Determine the delimiter for a text data file.

In reader: Suite of Functions to Flexibly Read Data from Files

Description

Reads the first few lines of data in a text file and attempts to infer what delimiter is in use, based on the 'delims' argument that would result in the most consistent number of columns in the first 'n' lines of data. Searches preferentially for delimiters implying between 2 and 'large' columns, then for >large, and lastly for 1 column if nothing else gives a match.

Usage

get.delim(fn, n = 10, comment = "#", skip = 0, delims = c("\t",
  "\t| +", " ", ";", ","), large = 10, one.byte = TRUE)

Arguments

fn	name of the file to parse
n	the number of lines to read to make the inference
comment	a comment symbol to ignore lines in files
skip	number of lines to skip at top of file before processing
delims	the set of delimiters to test for
large	search initially for delimiters that imply more than 1, and less than this 'large' columns; if none in this range, look next at >large.
one.byte	only check for one-byte delimiters, [e.g, whitespace regular expr is >1 byte]

Value

returns character of the most likely delimiter

Author(s)

Nicholas Cooper [e-mail]

See Also

reader

Examples

orig.dir <- getwd(); setwd(tempdir()); # move to temporary dir
df <- data.frame(ID=paste("ID",101:110,sep=""),
  scores=sample(70,10,TRUE)+30,age=sample(7,10,TRUE)+11)
# save data to various file formats
test.files <- c("temp.txt","temp2.txt","temp3.csv")
write.table(df,file=test.files[1],col.names=FALSE,row.names=FALSE,sep="|",quote=TRUE)
write.table(df,file=test.files[2],col.names=TRUE,row.names=TRUE,sep="\t",quote=FALSE)
write.csv(df,file=test.files[3])
# report the delimiters
for (cc in 1:length(test.files)) { 
  cat("\n",test.files[cc],": ")
  print(get.delim(test.files[cc])) }
unlink(test.files)
setwd(orig.dir) # reset working dir to original

Example output

Loading required package: NCmisc

Attaching package: 'reader'

The following objects are masked from 'package:NCmisc':

    cat.path, get.ext, rmv.ext


 temp.txt : [1] NA

 temp2.txt : [1] "\t"

 temp3.csv : [1] ","
Warning message:
In get.delim(test.files[cc]) : not a delimited file, probably a vector file

reader documentation built on May 2, 2019, 9:27 a.m.