Hi. I'm a D newbie(!) coming from a Fortran/C/Python background.
I'm
struggling with the many new concepts needed in order to make any
sense out
of the documentation or traceback messages
(ranges/templates/...). For
example, the std.csv documentation is great but all the examples
read from a
string rather than a file. I feel stupid but I'm having trouble
with the
simple step of modifying the examples to read from a file. I can
read the
whole file into a string in memory and then read the records from
the string
just fine with csvReader (example A below) or read a line at a
time from
the file and call csvReader using a single line (example B
below), but
neither solution is satisfactory. In practice I need to read
files with
up to 80 million records so I'd like to understand how to do this
properly/efficiently.
tia, Gerald
Example A
=========
import std.stdio, std.file, std.csv;
void main()
{
std.file.write("test.csv", "0,1,abc\n2,3,def");
scope(exit) std.file.remove("test.csv");
auto lines = readText!(string)("test.csv");
struct Rec { int a,b; char[] c; }
foreach (Rec r; csvReader!Rec(lines)) {
writeln("struct -> ", r);
}
}
Example B
=========
import std.stdio, std.file, std.csv;
void main()
{
std.file.write("test.csv", "0,1,abc\n2,3,def");
scope(exit) std.file.remove("test.csv");
struct Rec { int a,b; char[] c; }
Rec r;
foreach (line; File("test.csv", "r").byLine) {
r = csvReader!Rec(line).front;
writeln("struct -> ", r);
}
}
Output
======
struct -> Rec(0, 1, "abc")
struct -> Rec(2, 3, "def")
