替换所有不以\\\\开头的\\\\

Question

This should be simple. I want to change all of these substrings:

\\somedrive\some\path

into

file://\\somedrive\some\path

but if substrings already have a file:// then I don't want to append it again.

This doesn't seem to do anything:

var_export( str_replace( '\\\\', 'file://\\\\', '\\somedrive\some\path file://\\somedrive\some\path' ) ); 

What am I doing wrong? Also, the above doesn't take into test for file:// already being there; what's the best way of dealing with this?

UPDATE test input:

$test = '
file://\\someserver\some\path

\\someotherserver\path
';

test output:

file://\\someserver\some\path

file://\\someotherserver\path

Thanks.

Answer 1

You should consider escape sequence in string also.

if((strpos($YOUR_STR, '\\\\') !== false) && (strpos($YOUR_STR, 'file://\\\\') === false))
    var_export( str_replace( '\\\\', 'file://\\\\', $YOUR_STR ) ); 

Answer 2

Use a regular expression to check if the given substring starts with file:// . If it does, don't do anything. If it doesn't, append file:// at the beginning of the string:

if (!preg_match("~^file://~i", $str)) {
    $str = 'file://' . $str;
}

As a function:

function convertPath($path) {
    if (!preg_match("~^file://~i", $path)) {
        return 'file://'.$path;
    }
    return $path;
}

Test cases:

echo convertPath('\\somedrive\some\path');
echo convertPath('file://\\somedrive\some\path');

Output:

file://\somedrive\some\path
file://\somedrive\some\path

Answer 3

编辑多次出现： preg_replace('#((?!file://))\\\\\\\\#', '$1file://\\\\\\\\', $path)

Answer 4

This will work to give you the output you are expecting. As php.net says double slash will be converted into single slash.

if (!preg_match('/^file:\/\//', $str)) {
    $str =  "file://\\".stripslashes(addslashes($str));
}

Answer 5

Please try this:

$string = "\\somedrive\some\path";
$string = "\\".$string;
echo str_replace( '\\\\', 'file://\\\\',$string);