Retract #20524 since it was due to broken INT32_MIN in

[p5sagit/p5-mst-13.2.git] / pod / perlfaq4.pod

diff --git a/pod/perlfaq4.pod b/pod/perlfaq4.pod
index f7215e2..5e10a11 100644 (file)
--- a/pod/perlfaq4.pod
+++ b/pod/perlfaq4.pod
@@ -1,6 +1,6 @@
 =head1 NAME
 
-perlfaq4 - Data Manipulation ($Revision: 1.39 $, $Date: 2003/01/03 20:06:21 $)
+perlfaq4 - Data Manipulation ($Revision: 1.44 $, $Date: 2003/07/28 17:35:21 $)
 
 =head1 DESCRIPTION
 
@@ -142,7 +142,7 @@ Using the CPAN module Bit::Vector:
 
 =item How do I convert from decimal to hexadecimal
 
-Using sprint:
+Using sprintf:
 
     $hex = sprintf("%X", 3735928559);
 
@@ -316,7 +316,7 @@ Get the http://www.cpan.org/modules/by-module/Roman module.
 If you're using a version of Perl before 5.004, you must call C<srand>
 once at the start of your program to seed the random number generator.
 
-        BEGIN { srand() if $[ < 5.004 }
+        BEGIN { srand() if $] < 5.004 }
 
 5.004 and later automatically call C<srand> at the beginning.  Don't
 call C<srand> more than once---you make your numbers less random, rather
@@ -353,13 +353,34 @@ C<random_int_in(50,120)>
 
 =head1 Data: Dates
 
-=head2 How do I find the week-of-the-year/day-of-the-year?
+=head2 How do I find the day or week of the year?
+
+The localtime function returns the day of the week.  Without an
+argument localtime uses the current time.
+
+    $day_of_year = (localtime)[7];
+    
+The POSIX module can also format a date as the day of the year or
+week of the year.
 
-The day of the year is in the array returned by localtime() (see
-L<perlfunc/"localtime">):
+       use POSIX qw/strftime/;
+       my $day_of_year  = strftime "%j", localtime;
+       my $week_of_year = strftime "%W", localtime;
+
+To get the day of year for any date, use the Time::Local module to get
+a time in epoch seconds for the argument to localtime.
+       
+       use POSIX qw/strftime/;
+       use Time::Local;
+       my $week_of_year = strftime "%W", 
+               localtime( timelocal( 0, 0, 0, 18, 11, 1987 ) );
 
-    $day_of_year = (localtime(time()))[7];
+The Date::Calc module provides two functions for to calculate these.
 
+       use Date::Calc;
+       my $day_of_year  = Day_of_Year(  1987, 12, 18 );
+       my $week_of_year = Week_of_Year( 1987, 12, 18 );
+       
 =head2 How do I find the current century or millennium?
 
 Use the following simple functions:
@@ -741,6 +762,19 @@ case", but that's not quite accurate.  Consider the proper
 capitalization of the movie I<Dr. Strangelove or: How I Learned to
 Stop Worrying and Love the Bomb>, for example.
 
+Damian Conway's L<Text::Autoformat> module provides some smart
+case transformations:
+
+    use Text::Autoformat;
+    my $x = "Dr. Strangelove or: How I Learned to Stop ".
+      "Worrying and Love the Bomb";
+
+    print $x, "\n";
+    for my $style (qw( sentence title highlight ))
+    {
+        print autoformat($x, { case => $style }), "\n";
+    }
+
 =head2 How can I split a [character] delimited string except when inside [character]?
 
 Several modules can handle this sort of pasing---Text::Balanced,
@@ -811,9 +845,6 @@ values of a hash if you use a slice:
 
 =head2 How do I pad a string with blanks or pad a number with zeroes?
 
-(This answer contributed by Uri Guttman, with kibitzing from
-Bart Lateur.)
-
 In the following examples, C<$pad_len> is the length to which you wish
 to pad the string, C<$text> or C<$num> contains the string to be padded,
 and C<$pad_char> contains the padding character. You can use a single
@@ -828,13 +859,16 @@ right with blanks and it will truncate the result to a maximum length of
 C<$pad_len>.
 
     # Left padding a string with blanks (no truncation):
-    $padded = sprintf("%${pad_len}s", $text);
+       $padded = sprintf("%${pad_len}s", $text);
+       $padded = sprintf("%*s", $pad_len, $text);  # same thing
 
     # Right padding a string with blanks (no truncation):
-    $padded = sprintf("%-${pad_len}s", $text);
+       $padded = sprintf("%-${pad_len}s", $text);
+       $padded = sprintf("%-*s", $pad_len, $text); # same thing
 
     # Left padding a number with 0 (no truncation):
-    $padded = sprintf("%0${pad_len}d", $num);
+       $padded = sprintf("%0${pad_len}d", $num);
+       $padded = sprintf("%0*d", $pad_len, $num); # same thing
 
     # Right padding a string with blanks using pack (will truncate):
     $padded = pack("A$pad_len",$text);
@@ -958,13 +992,13 @@ Stringification also destroys arrays.
     print "@lines";            # WRONG - extra blanks
     print @lines;              # right
 
-=head2 Why don't my <<HERE documents work?
+=head2 Why don't my E<lt>E<lt>HERE documents work?
 
 Check for these three things:
 
 =over 4
 
-=item There must be no space after the << part.
+=item There must be no space after the E<lt>E<lt> part.
 
 =item There (probably) should be a semicolon at the end.
 
@@ -1870,7 +1904,7 @@ it on top of either DB_File or GDBM_File.
 Use the Tie::IxHash from CPAN.
 
     use Tie::IxHash;
-    tie my %myhash, Tie::IxHash;
+    tie my %myhash, 'Tie::IxHash';
     for (my $i=0; $i<20; $i++) {
         $myhash{$i} = 2*$i;
     }