I came upon the following, which seems to be in line with spec, but I
think is inconsistent.
I write a hash to a file delimited by tabs, eg
my $fn=open('data.csv',:w);
my %x=<one two three four> Z 1,2,2.1,3;
$fn.say('record-name'~map("\t$^a\t$^b"),%x);
$fn.close;
The output sometimes contains either the keys or the values padded with
single spaces on either side (I cannot find a pattern for the spaces). I
am not sure whether this a bug of say (or $fn.say() ).
So now I want to read in the data again. (The problem arises because
perl6 has a memory leak and my program segfaults after five loops, so I
need to store the intermediate data; this is a serialisation problem,
but I dont need to go to the extreme of yaml for it).
my $fn=open('data.csv',:r);
my $record-name;
my @fields;
($record-name,@fields)=$fn.lines(1).split(/\t/);
my %x = %(map{$^a => $^b}, @fields);
Except that the spaces added by .say are included in the key/value
parts. This screws up the program as spaces are not expected.
The spec specifically says that split will not trim the results. Hence,
the solution is
($record-name,@fields)=map {.trim}, $fn.lines(1).split(/\t/);
This does seem to be a bit inconsistent in that I am outputting and
inputting with essentially the same sort of scripting, but I am not
getting a predictable end result.
The spec also seems to recommend .comb
I have a problem with this because some of the data I want to read in
has empty cells, eg.
datum1\tdatum2\t\tend-datum
I want this to end up in an array
['datum1','datum2',*,'end-datum']
Yet I cant see how .comb will accomplish this. Could someone enlighten me?
But even if it was not a problem with .say, I could see that white space
trimming would be useful with split.
So, is there some good reason why .split does not automatically trim?
Richard
