PHP REGEX -删除多余的换行符-字符串操作问题 - PHP REGEX - removal of excess line breaks - String Manipulation Issue

PHP REGEX - removal of excess line breaks - String Manipulation Issue

我正在输入一个脏字符串(大量空格，换行符和标点符号前额外的假空格)

我想要的输出在下面的代码中解释。

似乎我可以实现删除多余的空格+来删除标点符号之前的空格。但是我的输出仍然有多余的换行符

当我从MySQL数据库打印用户输入到屏幕时，我使用了下面的函数。

echo "'t't".'<p>'.nl2br(convert_str(htmlspecialchars($comment))).'</p>'."'r'n";

我的定制函数代码如下:

function convert_str ($str)
{
    // remove excess whitespace
    // looks for a one or more spaces and replaces them all with a single space.
    $str = preg_replace('/ +/', ' ', $str);
    // check for instances of more than two line breaks in a row
    // and then change them to a total of two line breaks
    //did not worked for me --> preg_replace('/(?:(?:'r'n|'r|'n)'s*){2}/s', "'n'n", $str);
    $str = preg_replace('/[ 't]+/', ' ', preg_replace('/'s*$^'s*/m', "'n", $str));
    // if exists; remove 1 space character just before punctuations below:
    // $punc = array('.',',',';',':','...','?','!','-','—','/','''','“','”','‘','’','"','''','(',')','[',']','’','{','}','*','&','#','^','<','>','|');
    $punc = array(' .',' ,',' ;',' :',' ...',' ?',' !',' -',' —',' /',' ''',' “',' ”',' ‘',' ’',' "',' ''',' (',' )',' [',' ]',' ’',' {',' }',' *',' &',' #',' ^',' <',' >',' |');
    $replace = array('.',',',';',':','...','?','!','-','—','/','''','“','”','‘','’','"','''','(',')','[',']','’','{','}','*','&','#','^','<','>','|');
    $str = str_replace($punc,$replace,$str);
    return $str;
}

你能纠正我吗?

:我使用准备好的语句将用户输入输入到MySQL数据库表中，并且在进入数据库时不操作用户数据。

我发现了一个简单但耗时5小时的原因:只使用'n而不使用'r'n。

所以满足我要求的代码是:

function convert_str ($str)
{
    // remove excess whitespace
    // looks for a one or more spaces and replaces them all with a single space.
    $str = preg_replace('/ +/', ' ', $str);
    // check for instances of more than two line breaks in a row
    // and then change them to a total of two line breaks
    $str = preg_replace('/(?:(?:'r'n|'r|'n)'s*){2}/s', "'r'n'r'n", $str);
    // if exists; remove 1 space character just before punctuations below:
    // $punc = array('.',',',';',':','...','?','!','-','—','/','''','“','”','‘','’','"','''','(',')','[',']','’','{','}','*','&','#','^','<','>','|');
    $punc = array(' .',' ,',' ;',' :',' ...',' ?',' !',' -',' —',' /',' ''',' “',' ”',' ‘',' ’',' "',' ''',' (',' )',' [',' ]',' ’',' {',' }',' *',' &',' #',' ^',' <',' >',' |');
    $replace = array('.',',',';',':','...','?','!','-','—','/','''','“','”','‘','’','"','''','(',')','[',']','’','{','}','*','&','#','^','<','>','|');
    $str = str_replace($punc,$replace,$str);
    return $str;
}