Read and Write Delimited Text Files

There is nothing sophisticated about this approach to reading delimited text files. For all files, read-delimited produces a list of lists of strings. There is no attempt to convert strings to numbers or other objects. The file contents needs to be rectangular, i.e., every row must have the same number of columns. For an alternative approach, see chez-csv.

(read-delim path [sep-char max-rows])

returns: a list of lists where each sub-list is one row in the file at path; sep-char and max-rows are optional and default to #\, and +inf.0, respectively

(write-delim lst path [sep-char overwrite])

writes: a list of lists lst as a delimited text file to path; sep-char and overwrite are optional and default to #\, and #t, respectively.

Example

> (define example-list (list
                        (list "col1" "col2" "col3" "col4")
                        (list 10.02 #\A "1,000" "Glen \"Big Baby\" Davis")
                        (list 1/3 #\B "1000" "Earvin \"Magic\" Johnson")))

> (display example-list)
((col1 col2 col3 col4) (10.02 A 1,000 Glen "Big Baby" Davis) (1/3 B 1000 Earvin "Magic" Johnson))

> (write-delim example-list "example.csv")

> (read-delim "example.csv")
(("col1" "col2" "col3" "col4")
  ("10.02" "A" "\"1,000\"" "\"Glen \"Big Baby\" Davis\"")
  ("0.3333333333333333" "B" "1000" "\"Earvin \"Magic\" Johnson\""))