PHP str_replace for back slash

Question

I need to replace \ with '' in following string.

$x = "FBU4061\0258";

When I do $x = str_replace('\\', '', $x);

It returns FBU40618,

Is there any workaround to get FBU40610258.

Note: I need to do this inside double quotes. Within single quotes it returns the desired value without problem.

@RensTillmann, It does not work with double quotes, please see my note — Shaolin, Nov 09 '15 at 05:07
Then create a variable and then do whatever you want? I don't understand why that would make a difference. — Rens Tillmann, Nov 09 '15 at 05:08
I think that the point where it's in double quotes is where it becomes too late. As soon as you use the variable, `\025` is converted to a character: https://eval.in/465229 — scrowler, Nov 09 '15 at 05:09
@RensTillmann, When you use double quoted strings, PHP does an escape sequence replacement, and \0 is the NUL byte. — Shaolin, Nov 09 '15 at 05:09
@RensTillmann, It would work with regular strings, but my scenario is a different case. See this http://stackoverflow.com/questions/17499955/understanding-what-u0000-is-in-php-json-and-getting-rid-of-it — Shaolin, Nov 09 '15 at 05:13
Note that stripslashes will work with both double and single quotes. — Rens Tillmann, Nov 09 '15 at 05:14
@RobbieAverill, Actually $x is coming form the database, what we need is json_encode($x, JSON_UNESCAPED_SLASHES). But we get the result of that value is "FBU4061\u00158", So we thought of removing the slash or replacing it before encoding. — Shaolin, Nov 09 '15 at 05:15
Can you `var_dump` the value of `$x` before you do anything to it? — scrowler, Nov 09 '15 at 05:17
Why not :) not much we can do to help you if you can't provide an accurate representation of the variable that you retrieve from the database — scrowler, Nov 09 '15 at 05:19
@RobbieAverill, sorry I misunderstood you. When I var_dump too "FBU40618" get this value. — Shaolin, Nov 09 '15 at 05:22
@RobbieAverill, this is a coincidence, when \ and 0 are together, it escapes the character when it is inside double quotes. — Shaolin, Nov 09 '15 at 05:23
Maybe solution would be to change the value in the query: https://dev.mysql.com/doc/refman/5.7/en/string-functions.html#function_replace — Rens Tillmann, Nov 09 '15 at 05:58

score 5 · Answer 1 · edited Jun 20 '20 at 09:12

What's probably confusing you here is that double quoted strings interpret this string very differently from a single quoted string. Your string "FBU4061\0258" in PHP will interpret the \02 part of your string as an STX (or start of text) character (i.e. ASCII character 02).

Just try run the code var_dump("FBU4061\0258"); in PHP and see for yourself how the output is not what you would expect. You can even do var_dump(bin2hex("FBU4061\0258")); and see the hexadecimal representation of your string for further clarification...

Example

var_dump(bin2hex('\02'));
// string(6) "5c3032"
var_dump(bin2hex("\02"));
// string(2) "02"

See the difference?

This is all thoroughly documented behavior in the manual.

\[0-7]{1,3} the sequence of characters matching the regular expression is a character in octal notation

So in order to get a string literal of FBU4061\0258 you must escape the backslash inside of double quoted strings.

$x = "FBU4061\\0258";
$x = str_replace('\\', '', $x);
var_dump($x); //string(11) "FBU40610258"

Notice this is because you are placing a string literal in your code. If this string were retrieved from your database, however, this interpolation wouldn't take place, because it's already a string literal.

Again ...

var_dump("FBU4061\\0258"); // string(12) "FBU4061\0258"
var_dump("FBU4061\0258");  // string(9) "FBU40618"

Look at the obvious difference in the length of the string!

I understand the problem and we are evaluating possible solutions. Thanks for the post — Shaolin, Nov 09 '15 at 06:39

score 2 · Accepted Answer · edited Apr 13 '17 at 12:42

Your best chance is to do a mysql replace query:

Change the value in the query:

SELECT REPLACE('http://yourdomain.com', 'http', 'https');

https://dev.mysql.com/doc/refman/5.7/en/string-functions.html#function_replace

You might also try this instead:

UPDATE table SET field_name = replace(field, 'http, 'https')

https://dba.stackexchange.com/questions/2261/how-do-i-remove-backslashes-from-records-in-mysql

Abhishek Sharma · Answer 3 · 2015-11-09T05:25:51.290

0

use php stripslashes

echo stripslashes('FBU4061\0258');

or try this code :-

function removeslashes($string)
{
    $string=implode("",explode("\\",$string));
    return stripslashes(trim($string));
}

$text="FBU4061\0258";
echo removeslashes($text);

Stripslashes more details

edited Nov 09 '15 at 05:25

answered Nov 09 '15 at 05:03

Abhishek Sharma

6,689
1
14
20

As I told above it can be done with single quotes, I need to use double quotes. If you use double quotes, you will see it does bot work – Shaolin Nov 09 '15 at 05:05
That doesn't have to be a problem? – Rens Tillmann Nov 09 '15 at 05:06
@RensTillmann, Please try and see, actually above value comes from the database and so it come with double quotes – Shaolin Nov 09 '15 at 05:08
@Rahautos the example in the question uses double quotes so this is not an accurate answer – scrowler Nov 09 '15 at 05:16

PHP str_replace for back slash

3 Answers3

Example

Again ...