CODEWITHSUNDEEP
perl
Zilore Mumba
Zilore Mumba

Reputation: 1500

Why am I having "Missing argument in printf at ..." in perl?

I have perl code where am printing to file. I give the format 

my $format = "%4d %2d %2d %2d %2d %2d" . " %7.2f" x 9 . "\n";

because I am writing year month day hour minute second and 9 float values. Then I write to my output file as

printf $format, @data;        # print data on the screen
printf OUT $format, @data;    # print data into the file

Both of the above statements print, but always with a warning of "Missing argument in printf at (line number)". What is the correct way of writing the formt and/or the printf. Please help.

Upvotes: 1

Views: 1360

Answers (1)

ikegami
ikegami

Reputation: 385655

This signifies that the format string requires more values than are contained in @data.

$ perl -we'my @data = qw( a b c ); printf "%s %s %s\n", @data;'
a b c

$ perl -we'my @data = qw( a b   ); printf "%s %s %s\n", @data;'
Missing argument in printf at -e line 1.
a b

In your case, the format string has 15 placeholders, but @data contains fewer than 15 elements.

Based on your comments, I think you want

printf $format, $Y, $m, $d, $H, $M, $S, @data;

This could also be written as follows:

my $ts = sprintf("%04-%02d-%02d %02d:%02d:%02d", $Y, $m, $d, $H, $M, $S);
my $format = "%s".( " %7.2f" x 9 )."\n";
printf $format, $ts, @data;

Most of time, you'll start with a epoch timestamp (as returned by time()). In that situation, one could use the following:

use POSIX qw( strftime );

my $ts = strftime("%Y-%m-%d %H:%M:%S", localtime(time()));
my $format = "%s".( " %7.2f" x 9 )."\n";
printf $format, $ts, @data;

(Note that local times without an time zone offset creates ambiguous timestamps during "fall back" to standard time in areas with daylight-saving time.)

Upvotes: 2

Related Questions