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|library(csv): Process CSV (Comma-Separated Values) data|
This library parses and generates CSV data. CSV data is represented in Prolog as a list of rows. Each row is a compound term, where all rows have the same name and arity.
Suppose we want to create a predicate table/6
from a CSV file that we know contains 6 fields per record. This can be
done using the code below. Without the option
this would generate a predicate table/N, where N is the number of fields
per record in the data.
?- csv_read_file(File, Rows, [functor(table), arity(6)]), maplist(assert, Rows).
separator(0';)parses a semicolon separated file.
true(default false), threat double quotes as a normal character.
false), strip leading and trailing blank space. RFC4180 says that blank space is part of the data.
#. After skipping comment lines this option causes csv//2 to skip empty lines. Note that an empty line may not contain white space characters (space or tab) as these may provide valid data.
true(default), use name/2 on the field data. This translates the field into a number if possible.
down, downcase atomic values. If
up, upcase them and if
preserve(default), do not change the case.
domain_error(row_arity(Expected), Found)if a row is found with different arity.
true), do not reject CSV files where lines provide a varying number of fields (columns). This can be a work-around to use some incorrect CSV files.
In addition to the options of csv_read_file/3, this predicate processes the option:
end_of_fileupon reaching the end of the input.
save_data(File) :- setup_call_cleanup( open(File, write, Out), forall(data(C1,C2,C3), csv_write_stream(Out, [row(C1,C2,C3)], )), close(Out)).