XP is just a number PerlMonks

### Re: Re^2: How to replace Tab with spaces not altering postion

by petral (Curate)
 on Oct 14, 2002 at 15:27 UTC ( #205114=note: print w/replies, xml ) Need Help??

join "", map{ \$_ . (/\n/ ? "" : " " x (8 - length() & 7)) } split /\t/
?

p

Replies are listed 'Best First'.
Re^4: How to replace Tab with spaces not altering postion
by Aristotle (Chancellor) on Oct 14, 2002 at 15:33 UTC
\$_ = "You\tare\tmaking\ttoo\tmany\tassumptions...";

Makeshifts last the longest.

Right, I was hurrying to put it up and leave.   Forgot to point out it only works for normal input files where each line ends in a newline.

Actually, your algorithm solves the problem without abandoning regexen.   Unless we're missing something, Larry was thinking along the lines of bart's logic above, that you have to know the new length of the line up to this point.   But you are just depending on the text in front of the present tab(s) to be aligned either with the beginning of the line or the previous tab stop, so there is no need to consider the entire preceding line segment:
```\$ perl -we'\$_="\t\tYou\tare\tmaking\t\ttoo\tmany\tassumptions...\t\t";

s/(^|[^\t]+)(\t+)/\$1." " x (length(\$2) * 8 - (length(\$1) & 7))/ge;
print'
You     are     making          too     many    assump
+tions...          \$

( s/(.*?)(\t+)/...
is simpler but presumably less efficient (which was your initial concern).   However, note that it will work correctly on a multiline string:
```\$ perl -we'\$_="\t\tYou\tare\tmaking\t\ttoo\n\tmany\tassumptions...\t";

s/(.*?)(\t+)/\$1." "x(length(\$2)*8-(length(\$1)&7))/ge;
print'
You     are     making          too
many    assumptions...  \$

p

Create A New User
Node Status?
node history
Node Type: note [id://205114]
help
Chatterbox?
 [Lady_Aleena]: Are you all sick of me discussing my reorganization? [Discipulus]: Lady_Aleena use Great::Flood really, start some little project with new eyes (and a DB) [Discipulus]: 'unless it rains' => 'a meno che NON piova'

How do I use this? | Other CB clients
Other Users?