Delete lines in a file

[Adam]

Hello:

I am trying to solve the following problem:

A file, on each line contains typically 5 columns (separated by tabs)
of numbers. Ocassionally, on a line, there appears a single number in
the first column. I want to delete occurrences of such lines (i.e.
lines that only contain a single number.

For example

1.2345 2.3456 3.4567 4.5678 5.6789 ---> Typical line
23 ---> Atypical line (delete this
occurence)

How can I do this in Perl ?

Thanks

 

[Jürgen Exner]

A file, on each line contains typically 5 columns (separated by tabs)
of numbers. Ocassionally, on a line, there appears a single number in
the first column. I want to delete occurrences of such lines (i.e.
lines that only contain a single number.

Your Question is Asked Frequently, see
perldoc -q "delete a line"

jue

 

[Paul Lalli]

Your Question is Asked Frequently, see
perldoc -q "delete a line"

I disagree that Tie::File is needed for this operation. This would
suffice, no?

perl -ni.bak -e'print unless /^\d+$/' file.txt

(obviously, may need to modify the regexp if decimals or other
representations of numbers are allowed on the atypical lines)

Paul Lalli

 

[J. Romano]

A file, on each line contains typically 5 columns (separated by tabs)
of numbers. Ocassionally, on a line, there appears a single number in
the first column. I want to delete occurrences of such lines (i.e.
lines that only contain a single number.

For example

1.2345 2.3456 3.4567 4.5678 5.6789 ---> Typical line
23 ---> Atypical line (delete this
occurence)

Try this:

In UNIX:
perl -ne 'print unless m/^\d+$/' input.txt > output.txt

In DOS (Win32):
perl -ne "print unless m/^\d+$/" input.txt > output.txt

The file "input.txt" will be the file you already have, and
"output.txt" will be the file that will be created, which will be
exactly like "input.txt" except that it won't have any lines
consisting of a single number (i.e., the atypical lines).

I hope this helps.

-- Jean-Luc