Question

I am currently facing a problem that seems easy to deal with but I haven’t been able to solve it so far. I have a “pipe separated value” file and I would like to remove all leading and trailing spaces on all values on every line. This file may contain several lines.

Example:

1|     | Field2     | Field3
2| 123 | Field2     |
3|     |            | Field3

What I want after removing the spaces:

1||Field2|Field3
2|123|Field2|
3|||Field3

What I have so far works as long as the last field (in this case Field3) is not NULL. This correspond to line 2 on the example above. When the last field is NULL it concatenates that line with the next one creating a bigger line than what is expected.

My code so far is this one:

$res =~ s/\s*\|\s*/\|/g;

As mentioned previously this works as long as the last field on all lines is not NULL. I have tried to come up with a regex that matches all occurrences of a pipe except the last one but without success so far.

Any idea how I could remove all spaces and maintain the line integrity?

Thanks in advance,

João

Answer 1

The regex /\s/ matches carriage-returns and newlines (amongst other things) as well as spaces and tabs, so your substitution will delete the trailing newline on records with null final fields.

Try

$res =~ s/[ \t]*\|[ \t]*/|/g;

or

$res =~ s/[ ]*\|[ ]*/|/g;

if you’re not interested in removing tab characters.

(The pipe in the replacement string doesn’t need escaping.)