什么是各种白色空间变体？

Question

I want to replace all kind of white spaces by an underscore.

But my problem is that there are many kinds of white spaces. Till now found is:

1. non-breaking space
2. en space
3. em space
4. thin space

I am using

preg_replace("/\p{Z}/", "_", $text);

I want a list of all Types of white spaces.

Answer 1

You may use

preg_replace("/\s/u", "_", $text);

The u modifier will make \s Unicode aware and it will match any Unicode whitespace chars.

Here is a test on a U+0020U+00A0U+1680U+2000U+2001U+2002U+2003U+2004U+2005U+2006U+2007U+2008U+2009U+200AU+202FU+205FU+3000U+2028U+2029TextU+000B \t string:

$text = "                　
    
    Text\x0B
\t";
$res = preg_replace("/\s/u", "_", $text);
echo $res; // => ___________________Text____

See the PHP demo

U+0020  SPACE
U+00A0  NO-BREAK SPACE
U+1680  OGHAM SPACE MARK
U+2000  EN QUAD
U+2001  EM QUAD
U+2002  EN SPACE
U+2003  EM SPACE
U+2004  THREE-PER-EM SPACE
U+2005  FOUR-PER-EM SPACE
U+2006  SIX-PER-EM SPACE
U+2007  FIGURE SPACE
U+2008  PUNCTUATION SPACE
U+2009  THIN SPACE
U+200A  HAIR SPACE
U+202F  NARROW NO-BREAK SPACE
U+205F  MEDIUM MATHEMATICAL SPACE
U+3000  IDEOGRAPHIC SPACE
U+2028  LINE SEPARATOR
U+2029  PARAGRAPH SEPARATOR
U+000A  LINE FEED 
U+000B  LINE TABULATION
U+000D  CARRIAGE RETURN (CR)
U+0009  CHARACTER TABULATION