Module `Csvlib.Csv`

type t = string list list: Representation of CSV files.

exception Bad_CSV_file of string: Badly formed CSV files throw this exception.

val lines : t -> int: Work out the number of lines in a CSV file.

val columns : t -> int: Work out the (maximum) number of columns in a CSV file. Note that each * line may be a different length, so this finds the one with the most * columns.

val load_in : ?⁠separator:char -> Stdlib.in_channel -> t

Load a CSV file. *

parameter chan: Input file stream

val load : ?⁠separator:char -> string -> t

Load a CSV file. *

parameter filename: CSV filename.

val load_string : ?⁠separator:char -> string -> t

Load a CSV from a string. *

parameter s: String whose contents is the entire CSV.

val load_rows : ?⁠separator:char -> (string list -> unit) -> Stdlib.in_channel -> unit

For very large CSV files which cannot be processed in memory at once, * this function is appropriate. It parses the input one row at a time and * calls your function once for each row. * * Note that if you CSV file contains cells which have embedded * line feeds, then it is non-trivial to parse these lines and * pass them correctly to load_rows. * *

parameter f

Callout function. *

@param chan

Input file stream.

val load_rows_inchar : ?⁠separator:char -> (string list -> unit) -> (unit -> char) -> unit: Works exactly like load_rows except that instead of reading from * a descriptor, it calls a read_char function. This function * throws End_of_file on the end of input.

val trim : ?⁠top:bool -> ?⁠left:bool -> ?⁠right:bool -> ?⁠bottom:bool -> t -> t: This takes a CSV file and trims empty cells. * * All four of the option arguments (~top, ~left, ~right, ~bottom) * default to true. * * The exact behaviour is: * * ~right: If true, remove any empty cells at the right hand end of * any row. The number of columns in the resulting CSV structure will * not necessarily be the same for each row. * * ~top: If true, remove any empty rows (no cells, or containing just empty * cells) from the top of the CSV structure. * * ~bottom: If true, remove any empty rows from the bottom of the * CSV structure. * * ~left: If true, remove any empty columns from the left of the * CSV structure. Note that ~left and ~right are quite different: * ~left considers the whole CSV structure, whereas ~right considers * each row in isolation.

val square : t -> t: Make the CSV data "square" (actually rectangular). This pads out * each row with empty cells so that all rows are the same length as * the longest row. After this operation, every row will have length * columns.

val associate : string list -> t -> (string * string) list list

associate header data takes a block of data and converts each * row in turn into an assoc list which maps column header to data cell. * * Typically a spreadsheet will have the format: *

  *   header1   header2   header3
  *   data11    data12    data13
  *   data21    data22    data23
  *     ...
  *

* * This function arranges the data into a more usable form which is * robust against changes in column ordering. The output of the * function is: *

  *   [ ["header1", "data11"; "header2", "data12"; "header3", "data13"];
  *     ["header1", "data21"; "header2", "data22"; "header3", "data23"];
  *     etc. ]
  *

* * Each row is turned into an assoc list (see List.assoc). * * If a row is too short, it is padded with empty cells (""). If * a row is too long, it is truncated. * * You would typically call this function as: * *

  * let header, data = match csv with h :: d -> h, d | [] -> assert false;;
  * let data = Csv.associate header data;;
  *

* * The header strings are shared, so the actual space in memory consumed * by the spreadsheet is not much larger.

val print : ?⁠separator:char -> t -> unit: Print string list list - same as save_out stdout

val save_fn : ?⁠separator:char -> (string -> unit) -> t -> unit: Save the string list list, writing the strings by calling the given * given functon.

val save_out : ?⁠separator:char -> Stdlib.out_channel -> t -> unit: Save string list list to a channel.

val save : ?⁠separator:char -> string -> t -> unit: Save string list list to a file.

val print_readable : t -> unit: Print the CSV data to stdout in a human-readable format. Not much * is guaranteed about how the CSV is printed, except that it will be * easier to follow than a "raw" output done with print. This is * a one-way operation. There is no easy way to parse the output of * this command back into CSV data.

val save_out_readable : Stdlib.out_channel -> t -> unit: As for print_readable, allowing the output to be sent to a channel.

val save_fn_readable : (string -> unit) -> t -> unit