Perl to fill the lost value with previous value

[tzeronone]

For example, I have a text file consist of this number


(#ID #number)
1 0.062
742 -1.953
744 0.176
910 -2.000
913 0.164

The #ID is a sequence number. Can see that ID#2 to ID#741, ID#743, ID#745 to ID#909, ID#911 to ID#912 are not recorded. My wish output is


(#ID #number)
1 0.062
2 0.062
3 0.062
:
740 0.062
741 0.062
742 -1.953
743 -1.953
744 0.176
745 0.176
:
909 0.176
910 -2.000
911 -2.000
912 -2.000
913 0.164


The number of the unknown ID will repeat with the number of the previous recorded ID. Any idea?

[Vaphell]

#! /usr/bin/perl -w
use strict;

my $prev_id = 0;
my $prev_val = 0;

while (<>)
{
my( $id, $val ) = split;
for( my $i=$prev_id+1; $i<$id; $i++ ) { printf( "%d %s\n", $i, $prev_val ); }
printf( "%d %s\n", $id, $val );
($prev_val, $prev_id) = ($val, $id);
}
------------------------------------------------
$ ./fill.pl <<< $'1 -0.222\n4 3.33\n9 1.01'
1 -0.222
2 -0.222
3 -0.222
4 3.33
5 3.33
6 3.33
7 3.33
8 3.33
9 1.01

[Tony Flury]

For example, I have a text file consist of this number


(#ID #number)
1 0.062
742 -1.953
744 0.176
910 -2.000
913 0.164

The #ID is a sequence number. Can see that ID#2 to ID#741, ID#743, ID#745 to ID#909, ID#911 to ID#912 are not recorded. My wish output is


(#ID #number)
1 0.062
2 0.062
3 0.062
:
740 0.062
741 0.062
742 -1.953
743 -1.953
744 0.176
745 0.176
:
909 0.176
910 -2.000
911 -2.000
912 -2.000
913 0.164


The number of the unknown ID will repeat with the number of the previous recorded ID. Any idea?


This looks horribly like homework - I can think of no practical reason for this - unless the OP can tell me otherwise ?

[tzeronone]

This looks horribly like homework - I can think of no practical reason for this - unless the OP can tell me otherwise ?

It practice how to bring the value of the second column to mathematical operation. Open your mind that nothing is impossible to learn.