How can I remove 0 from first line and empty space from the start of the following line and join them

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

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Re: How can I remove 0 from first line and empty space from the start of the following line and join them by BrowserUk (Patriarch) on Oct 16, 2002 at 02:19 UTC
Adapting this to read from your file and write to a new file should be easy. #! perl -sw use strict; while (<DATA>) { $_ .= <DATA>; s/^0\s(.)\n\s+(.\n)/$1 $2/s; print; } __DATA__ 0 54000 4.52402E+00 5.37331E+00 -5.37331E+00 -6.52528E-04 2.04301E-01 -1.07277E-03 0 54001 7.12575E+01 4.88288E+01 -4.88288E+01 -2.20964E-03 9.34513E-01 -1.76121E-03 0 54002 3.55673E+00 9.22908E+00 -9.22908E+00 1.05358E-04 1.78918E-01 1.74279E-04 0 54003 2.71198E+00 5.04349E+00 -5.04349E+00 0 1.73257E+00 4.45074E+00 0 54004 2.23790E+00 3.46888E+00 -3.46888E+00 -1.95970E-05 5.09952E-02 -1.95518E-05 0 54005 4.14851E+00 1.99183E+01 -1.99183E+01 -7.59083E-05 2.54499E-01 -1.53444E-04 [download] # Output C:\test>205602 54000 4.52402E+00 5.37331E+00 -5.37331E+00 -6.52528E-04 2.04301E-0 +1 -1.07277E-03 54001 7.12575E+01 4.88288E+01 -4.88288E+01 -2.20964E-03 9.34513E-0 +1 -1.76121E-03 54002 3.55673E+00 9.22908E+00 -9.22908E+00 1.05358E-04 1.78918E-01 + 1.74279E-04 54003 2.71198E+00 5.04349E+00 -5.04349E+00 0 1.73257E+00 4.45074E ++00 54004 2.23790E+00 3.46888E+00 -3.46888E+00 -1.95970E-05 5.09952E-0 +2 -1.95518E-05 54005 4.14851E+00 1.99183E+01 -1.99183E+01 -7.59083E-05 2.54499E-0 +1 -1.53444E-04 C:\test> [download] Cor! Like yer ring! ... HALO* dammit! ... 'Ave it yer way! Hal-lo, Mister la-de-da. ... Like yer ring!	[reply] [d/l] [select]
Re: Re: How can I remove 0 from first line and empty space from the start of the following line and join them by krusty (Hermit) on Oct 16, 2002 at 02:34 UTC
An efficient alternative to: `while (<DATA>) { $_ .= <DATA>; s/^0\s(.)\n\s+(.\n)/$1 $2/s; print; }` [download] is not to even loop at all. `{ local $/ = undef; $_ = <DATA>; s/^0\s(.)\n\s+(.\n)/$1 $2/s; print; }` [download] caveat is that it eats up memory if you have an extremely large file. Cheers, Kristina Update: See BrowserUK's post immediately below. /s would allow the "." to match the newline which I don't want to happen here, but /m will treat the single string as multiple lines and /g will let me match more than once before quitting.	[reply] [d/l] [select]
Re: Re: Re: How can I remove 0 from first line and empty space from the start of the following line and join them by BrowserUk (Patriarch) on Oct 16, 2002 at 02:40 UTC
It would.... if you added /mg options instead of /s to the regex. Cor! Like yer ring! ... HALO dammit! ... 'Ave it yer way! Hal-lo, Mister la-de-da. ... Like yer ring!	[reply] [d/l]
Re: How can I remove 0 from first line and empty space from the start of the following line and join them by sauoq (Abbot) on Oct 16, 2002 at 02:34 UTC
`perl -i.bak -n0e 's/0\s+(.)\n\s+(.)/$1 $2/g&&print' file` [download] This, a combination of BrowserUk's correct method and Enlil's short method, should do what you want in one line. -sauoq "My two cents aren't worth a dime.";	[reply] [d/l]
Re: How can I remove 0 from first line and empty space from the start of the following line and join them by arturo (Vicar) on Oct 16, 2002 at 02:28 UTC
Basic idea: read in two-line chunks (read one line, then another) Join the lines. Strip out the leading zero, and any excess whitespace (including newlines). `open FILE, "file.txt" or die "Can't open file.txt:$!\n"; while(my $firstline = <FILE>) { $secondline = <FILE> or die "Ran out of lines!\n"; # how to join the lines is left as an exercise for the # reader: hint ... Dot knows much. }` [download] For the second part, you can use a regular expression. Here's a hint: `/^a/` matches an a at the beginning of a string. Here's another hint: `\s{7,}` matches seven whitespace (space, tab, newline) characters. The general syntax for a search-and-replace (substitution) pattern match is `$string =~ s/tick/arthur/;`, and the `/g` modifier on the end of a regular expression tells the system to perform each match it finds (instead of just the first). The rest is left as an exercise for the reader. Study materials: perlre, perlretut. HTH Update theorbtwo pointed out I hadn't closed my ordered list tag. If not P, what? Q maybe? "Sidney Morgenbesser"	[reply] [d/l] [select]
Re: How can I remove 0 from first line and empty space from the start of the following line and join them by Enlil (Parson) on Oct 16, 2002 at 02:17 UTC
try this: `perl -pi.bak -e "s/^0\s+//;" file_name` [download] This will look for a 0 at the start of every line followed by spaces and remove them (if this pattern does not exist it leaves the line alone), and then print the line back out to file you pass it the i.bak will create a backup file with the filename as file_name.bak. I believe this is what you are asking for. UPDATE: I neglected the second line part. My mistake. See the responses below for a better more complete answer. -Enlil	[reply] [d/l]
Re: How can I remove 0 from first line and empty space from the start of the following line and join them by Aristotle (Chancellor) on Oct 16, 2002 at 14:16 UTC
If you only need to do this once, vim will do the job in a blink of an eye: `:%g/^0/norm 0dwJ` Doncha just love that editor. `:-)` Makeshifts last the longest.	[reply] [d/l]
Re: How can I remove 0 from first line and empty space from the start of the following line and join them by Anonymous Monk on Oct 16, 2002 at 14:09 UTC
Thanks to all who responded. Perlmonks is great!	[reply]
Re: How can I remove 0 from first line and empty space from the start of the following line and join them by antifun (Sexton) on Oct 16, 2002 at 15:19 UTC
Since a vim solution was posted, here's an awk one: `awk 'BEGIN { ORS=""; OFS="\t" } /^0/ {print $2, $3, $4, $5} /^[ \t]/ +{print $0, "\n" }'` [download] TMTOWTDI, even if it's not in perl :) --- "I hate it when I think myself into a corner." Matt Mitchell	[reply] [d/l]


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