Edit varaibles in file

indie_campbell has asked for the wisdom of the Perl Monks concerning the following question:

Hi, help on this is much needed. The following code works fine

local $/= "# input for ";
while (<FILE1>) {
        s/1\.00/5/g if /Data\b\n/;
        print;
                }
[download]

input file looks like:

# input for Data

1.00  0.99  0.92
1.00 -0.22  0.61
[download]

But now can i adjust the code so that it only edits 1.00 on first line only. This file goes on with Data1 Data2 etc with different pairs of lines. Thanks

20040331 Edit by Corion: Added formatting, code tags

Comment on Edit varaibles in file Select or Download Code

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Re: Edit variables in file by Roy Johnson (Monsignor) on Mar 31, 2004 at 15:43 UTC
How about using a flip-flop operator? `while (<DATA>) { /# input for/ .. s/1\.00/5/g; print; } __DATA__ # input for Data 1.00 0.99 0.92 1.00 -0.22 0.61` [download] or, to avoid warnings about "useless" use of flop, `use strict; use warnings; while (<DATA>) { if (/# input for/ .. /\d/) { s/1\.00/5/g } print; } __DATA__ # input for Data 1.00 0.99 0.92 1.00 -0.22 0.61` [download] The PerlMonk `tr///` Advocate	[reply] [d/l] [select]
Re: Edit varaibles in file by ccn (Vicar) on Mar 31, 2004 at 14:13 UTC
`local $/= "# input for "; my $done = 0; while (<FILE1>) { s/1\.00/5/g if /Data\b\n/ and !$done++; print; }` [download]	[reply] [d/l]
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Re: Edit varaibles in file by dragonchild (Archbishop) on Mar 31, 2004 at 14:30 UTC
In general, if you have special handling for the first line, you should handle the first line separately. This also makes it easier for people reading your code in six months. By breaking it up into two sections, you make it obvious that the first line is special (for whatever reason). ------ We are the carpenters and bricklayers of the Information Age. Then there are Damian modules.... sigh* ... that's not about being less-lazy -- that's about being on some really good drugs -- you know, there is no spoon.* - flyingmoose	[reply]
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Re: Edit varaibles in file by DamnDirtyApe (Curate) on Mar 31, 2004 at 19:11 UTC
Personally, I think I'd take this approach: `use Tie::File; tie my @arr, 'Tie::File', 'myfile.dat'; s(1\.00)(5) and last for @arr; untie @arr;` [download] _______________ DamnDirtyApe Those who know that they are profound strive for clarity. Those who would like to seem profound to the crowd strive for obscurity. --Friedrich Nietzsche	[reply] [d/l]


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