shift and push question in perl Post: 302123946

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Top Forums Shell Programming and Scripting shift and push question in perl Post 302123946 by hankooknara on Wednesday 27th of June 2007 11:11:33 PM

06-28-2007

Registered User

I think I understand now.. so basicalli this program goes through the whole file and rebuilds the file adding items (to the end so that first item is in the top)... and it will shift(take items from top) if it has more than 2... did I understand this correctly?

#!/usr/bin/perl -w

use strict;

open(FILE, '<', 'gettysburg.txt') or die $!;
my @last5;

while (<FILE>) {
push @last5, $_; # add to the end
print @last5;
shift @last5 if @last5 > 2; # take from the beginning
print @last5;
}

close FILE;

print "Last five lines:\n", @last5;

main::(tail1.pl:5): open(FILE, '<', 'gettysburg.txt') or die $!;
DB<1> s
main::(tail1.pl:6): my @last5;
DB<1>

1
main::(tail1.pl:9): push @last5, $_; # add to the end
DB<1>
main::(tail1.pl:10): print @last5;
DB<1>
1
2

DB<1>
2
3
main::(tail1.pl:15): close FILE;
DB<1>
main::(tail1.pl:17): print "Last five lines:\n", @last5;
DB<1>
Last five lines:
2
3

Last edited by vino; 06-28-2007 at 01:48 AM.. Reason: Disable smilies in text

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LEARN ABOUT X11R4

xkbkeysymentry

XkbKeySymEntry(3)						   XKB FUNCTIONS						 XkbKeySymEntry(3)

NAME

       XkbKeySymEntry -  Returns the keysym corresponding to shift level shift and group grp from the two-dimensional array of keysyms for the key
       corresponding to keycode

SYNOPSIS

       KeySym XkbKeySymEntry macro ( xkb, keycode, shift, grp )
	     XkbDescPtr xkb;
	     KeyCode keycode;
	     int shift;
	     int grp;

ARGUMENTS

       - xkb  Xkb description of interest

       - keycode
	      keycode of interest

       - shift
	      shift level of interest

       - grp  group of interest

DESCRIPTION

       The key width and number of groups associated with a key are used to form a small two-dimensional array of KeySyms for a  key.  This  array
       may be different sizes for different keys. The array for a single key is stored as a linear list, in row-major order. The arrays for all of
       the keys are stored in the syms field of the client map. There is one row for each group associated with a key  and  one  column  for  each
       level. The index corresponding to a given group and shift level is computed as:

	    idx = group_index * key_width + shift_level

       The offset field of the key_sym_map entry for a key is used to access the beginning of the array.

       XkbKeySymEntry  returns	the  keysym corresponding to shift level shift and group grp from the two-dimensional array of keysyms for the key
       corresponding to keycode.

X Version 11							   libX11 1.2.1 						 XkbKeySymEntry(3)