Problems reading header line from my Excel 2007 files created with Perl - perl

Question

I have a problem with merging two dynamically created Excel 2007 files.
My files are created with the Perl Module Excel::Writer::XLSX on Solaris.
Say I have two files, fileA.xlsx and fileB.xlsx. Now I want to merge them together (fileA + fileB => fileC).
It is not really possible at this time to append fileB to fileA. This is a limitation of Excel::Writer::XLSX, which can only create new files.
Both .xlsx files can be opened without complaints in Excel 2007, in LibreOffice 3 (on linux), and (with the help of Microsoft's xlsx to xls converters) even in Excel 2003.
However, when I open them with perl (using the module Spreadsheet::XLSX), the contents of the header row, (row 0) are always skipped;
# ...
foreach my $infile (#infiles) {
my $excel = Spreadsheet::XLSX->new($infile);
my $i = 0;
foreach my $sheet ( #{ $excel->{Worksheet} } ) {
printf( "Infile '$infile', Sheet $i: %s\n", $sheet->{Name} );
$sheet->{MaxRow} ||= $sheet->{MinRow};
print "$infile: " . $sheet->{MaxRow} . " rows\n";
print "data starts at row: " . $sheet->{MinRow} . ". \n";
next unless $i == 0; # only copy data from the first sheet (for speed)
my $start_row = $sheet->{MinRow};
foreach my $row ( $start_row .. $sheet->{MaxRow} ) {
$sheet->{MaxCol} ||= $sheet->{MinCol};
foreach my $col ( $sheet->{MinCol} .. $sheet->{MaxCol} ) {
my $cell = $sheet->{Cells}[$row][$col];
if ($cell) {
# do something with the data
# ...
# write to outfile
$excel_writer->sheets(0)->write($dest_row, $col, $cell->{Val} )
}
}
}
}
}
Now, the ouput of this code fragment is always
data starts at row: 1.
But this is not true, it starts at row 0. If I manually go to read in data from row0, $cell is undefined (although it shouldn't be).
Interestingly, when I open the file in Microsoft Excel, and change it trivially, (say, by adding a blank space to one of the cell values in the header row), and save the file, then the header row IS found by the code above.
data starts at row: 0.
By the way, when I open, change, save the file in LibreOffice, there are numerous warnings concerning date values when I re-read them with the code above. (Thus, datetime values seem to be saved slightly incorrectly by LibreOffice).
The code that produces the files looks like this (note: some vars are defined outside of this sub):
sub exportAsXLS {
#require Spreadsheet::WriteExcel;
require Excel::Writer::XLSX;
my ( $data, $dir, $sep, #not2export ) = #_;
my $val;
my $EXCEL_MAXROW = 1048576;
return undef unless $data;
return "." unless scalar #$data > 0;
my $time = time2str( "%Y%m%d_%H%M%S", time() );
my $file = "$outdir/$dir/${host}_${port}-${time}.xlsx";
#my $workbook = Spreadsheet::WriteExcel->new($file);
my $workbook = Excel::Writer::XLSX->new($file);
$workbook->set_optimization();
my $worksheet = $workbook->add_worksheet();
# Set the default format for dates.
#my $date_formatHMS = $workbook->add_format( num_format => 'mmm d yyyy hh:mm AM/PM' );
#my $date_formatHMS = $workbook->add_format( num_format => 'yyyy-mm-ddThh:mm:ss.sss' );
my %formats;
$formats{date_HM} = $workbook->add_format( num_format => 'yyyy-mm-ddThh:mm' );
$formats{date_HMS} = $workbook->add_format( num_format => 'yyyy-mm-ddThh:mm:ss' );
$formats{num} = $workbook->add_format();
$formats{num}->set_num_format();
$formats{headline} = $workbook->add_format();
$formats{headline}->set_bold();
$formats{headline}->set_num_format('#');
# Format as a string. use the Excel text format #:
# Doesn't change to a number when edited
$formats{string} = $workbook->add_format( num_format => '#' );
$worksheet->set_row( 0, 15, $formats{headline} );
my $row = 0;
my $col = 0;
for ( my $r = -1 ; $r < #$data && $r < $EXCEL_MAXROW ; $r++ ) {
for ( my $i = 0 ; $i < #$column ; $i++ ) {
next if grep( $_ eq $column->[$i], #not2export );
my $val = $data->[$r]{ $column->[$i] };
my $t = int $type->[$i];
if ( $r < 0 ) {
#warn " type: $type->[$i] , ";
# Erste Zeile = Spaltennamen ausgeben
$worksheet->write_string( $row, $col++, $column->[$i], $formats{string});
#$worksheet->write_comment( 0, 0, "\x{263a}" ); # Smiley
#$worksheet->write( $row, $col++, $column->[$i], $formats{headline} );
} elsif ( ( $t == 11 ) or ( $t == 9 ) ) {
# 11 - Der Wert ist ein Datum, im SHORT Format, 9- long
$val = time2str( "%Y-%m-%dT%H:%M:%S", str2time( $data->[$r]{ $column->[$i] } ) );
$worksheet->write_date_time( $row, $col++, $val, $formats{date_HMS} );
} else {
$worksheet->write( $row, $col++, $val );
}
}
$col = 0;
$row++;
}
return $file;
}
The difference between the files is as follows.
On the left is the file that Excel::Writer::XLSX produces. ON the right is the file that MS Excel 2003 produces after a trivial change to the header row. the row header data is refactored, externalized to a different file, sharedStrings.xml
Which looks like this.
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<sst xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main" count="5" uniqueCount="5">
<si>
<t>SITE</t>
</si>
<si>
<t>LOG_DATE</t>
</si>
<si>
<t>KTZI201_WF_TEMPERATUR</t>
</si>
<si>
<t>KTZI300_TEMP_RESERVOIR</t>
</si>
<si>
<t>XPEDITION</t>
</si>
</sst>
Spreadsheet::XLSX can read the header if the .xlsx file is formatted as shown on the right half of the picture, but skips the header row when formatted as shown on the left half.

Answer 1

When I run your program against the output of this Excel::Writer::XLSX example program it correctly reports data in the first row (row == 0):
Infile 'a_simple.xlsx', Sheet 0: Sheet1
a_simple.xlsx: 10 rows
data starts at row: 0.
Perhaps you should double check the program that is producing the input files.
Also, make sure you are on the latest version of Excel::Writer::XLSX.