How do I replace \t and regarding to the alignment requirement ?

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

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Re: How do I replace \t and regarding to the alignment requirement ? by BrowserUk (Patriarch) on Apr 19, 2012 at 14:06 UTC
Like this? `$s = "The\tquick\tbrown\tfox\tjumps\tover\tthe\tlazy\tdog";; print $s;; The quick brown fox jumps over the lazy dog ($t=$s); 1 while $t =~ s[(\t)]{ '.' x ( 8 - ( $-[0] % 8 ) ) }e; print $t;; The.....quick...brown...fox.....jumps...over....the.....lazy....dog` [download] With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday' Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice. The start of some sanity?	[reply] [d/l]
Re: How do I replace \t and regarding to the alignment requirement ? by Corion (Patriarch) on Apr 19, 2012 at 13:34 UTC
Searching for tab expand and tabs only yields the `expand` and `unexpand` programs in ppt. They even do seem to support arbitrary tab stops. I would look at ripping the code out of one of these, as there doesn't seem to be a `Text::` module that provides that functionality. Aaahah. Searching for tabstop finds Text::Format, which claims to have `->expand` as a subroutine.	[reply] [d/l] [select]
Re^2: How do I replace \t and regarding to the alignment requirement ? by PerlOnTheWay (Monk) on Apr 19, 2012 at 13:49 UTC
`expand` blindly replaces 1 tab with 8 spaces,so it's not fit for this task...	[reply] [d/l]
Re^3: How do I replace \t and regarding to the alignment requirement ? by Corion (Patriarch) on Apr 19, 2012 at 13:55 UTC
Weird - at least this version of expand works for me, and the source code suggests that it should work just as it does: `Q:\>copy con test.txt blah a blah ^Z 1 file(s) copied. Q:\>perl -w expand.pl test.txt blah a blah Q:\>perl -w expand.pl test.txt\|perl -ple "s!\t!x!g" blah a blah Q:\>perl -w expand.pl test.txt\|perl -ple "s! !_!g" blah____a_______blah Q:\>type test.txt\|perl -ple "s! !_!g" blah a blah` [download] If `expand` is not working for you, maybe the code I linked to does work for you and you can reuse that?	[reply] [d/l] [select]
Re: How do I replace \t and regarding to the alignment requirement ? by JavaFan (Canon) on Apr 19, 2012 at 13:47 UTC
`my @l = (0, 7, 6, 5, 4, 3, 2, 1); $str =~ s/\G([^\t]*)\t/$1 . (' ' x $l[length($1) % 8])/eg;` [download] I'm sure it can be done with a closed formula instead of a lookup table, but this was faster coding.	[reply] [d/l]
Re^2: How do I replace \t and regarding to the alignment requirement ? by PerlOnTheWay (Monk) on Apr 19, 2012 at 14:20 UTC
This doesn't work for multiple lines.	[reply]
Re^3: How do I replace \t and regarding to the alignment requirement ? by JavaFan (Canon) on Apr 19, 2012 at 14:26 UTC
Sure it does. Unless you mean that you want to restart counting offsets on each newline. But you didn't specify that.	[reply]
Re^4: How do I replace \t and regarding to the alignment requirement ? by PerlOnTheWay (Monk) on Apr 19, 2012 at 14:28 UTC
Re^5: How do I replace \t and regarding to the alignment requirement ? by JavaFan (Canon) on Apr 19, 2012 at 14:30 UTC
Some notes below your chosen depth have not been shown here
Re^3: How do I replace \t and regarding to the alignment requirement ? by Anonymous Monk on Apr 19, 2012 at 14:23 UTC
And what should it do for multiple lines?	[reply]
Re: How do I replace \t and regarding to the alignment requirement ? by Utilitarian (Vicar) on Apr 19, 2012 at 14:27 UTC
And without using the @LAST_MATCH_START variable, because I thought it was an evil which tainted any other regex used in the program (though I may be completely mistaken in this) `perl -Mstrict -we 'my $string="random\ttab\tseparated\twords"; sub tab2space{my ($string,$spacing)=@_; while($string=~/\\t/){ print $string,"\n"; my $index=index($string,"\\t"); $string=~s/\\t/" " x ($index %8)/e; } return $string} for (0..80){print $_ % 10;} print "\n", tab2space($string) , "\n";' 0123456789012345678901234567890123456789012345678901234567890123456789 +01234567890 random tab separated words` [download] `print "Good ",qw(night morning afternoon evening)[(localtime)[2]/6]," fellow monks."`	[reply] [d/l] [select]
Re^2: How do I replace \t and regarding to the alignment requirement ? by AnomalousMonk (Archbishop) on Apr 22, 2012 at 16:02 UTC
... `@LAST_MATCH_START` variable ... an evil which tainted any other regex ... You may be thinking of `$&` (`$MATCH`) and friends ($` and `$'`). While `@LAST_MATCH_START` (`@-`) may share in the general overhead associated with capturing, I am not aware that it is touched by the evil of `$&` and its ilk. And with 5.10+, the incantation of the /p regex modifier can raise even $` $& $' to purity as the `${^PREMATCH} ${^MATCH} ${^POSTMATCH}` special variables. Oh, happy day!	[reply] [d/l] [select]
Re: How do I replace \t and regarding to the alignment requirement ? by Anonymous Monk on Apr 19, 2012 at 13:33 UTC
It is unclear what you're trying to accomplish `my $input = "blah\tblah\tblah"; my $wanted = ...;` [download] FWIW, a regex can't do nothing, substitution operator does stuff	[reply] [d/l]
Re^2: How do I replace \t and regarding to the alignment requirement ? by Anonymous Monk on Apr 19, 2012 at 14:02 UTC
input :blah\ta\tblah output:blah(4spaces)a(7spaces)blar :) That is not $input and $output :) `$ perl -MPerl6::Form -le " print form q{{:[{8}]:}} x 3, qw/ blah a bla +h / " blah a blah` [download] `12345678 12345678 12345678` [download]	[reply] [d/l] [select]


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