Question 266944 in PHP Question posted in
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Php – How to remove blank lines in a quick way (regex?)

an external program generates a file for me like this:

"lorem ipsum",

"lorem ipsum",
"lorem ipsum",

"lorem ipsum"

and I want to obtain:

"lorem ipsum",
"lorem ipsum",
"lorem ipsum",
"lorem ipsum"

I would like to remove these free spaces made by creating a new line, I was thinking about regex but I have no idea how to do it.

I tried regex but didn’t find query

Tags:

2

Answers


  1. 0

    In PHP function preg_replace is used for replacing by regex. Actual regex is based matching multiple consecutive new line (n) by single one.

    <?php
$str = '"lorem ipsum",

"lorem ipsum",
"lorem ipsum",

"lorem ipsum"
';

echo("<pre>" . preg_replace('/n+/', "n", $str) . "</pre>");
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  2. 0

    The idea: match all white-space sequence greedily and let the regex engine backtrack if needed until an end of line.

    $str = '
"lorem ipsum",

"lorem ipsum",
"lorem ipsum",

"lorem ipsum"
';

$str = preg_replace('~s+$~mu', '', $str);

echo $str;

    Pro:

    • It works with any newline sequence and do not change it.
    • It removes as well trailing blank lines
    • It removes also blank lines that eventually contains a space or any other white character.

    Cons:

    • It right-trims each line, that may be an unwanted behavior.
    • It removes leading blank lines except one. So an additional step is needed to trim it. (eventually the pattern can be changed to ~As*R|s+$~mu)
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