I have a form which takes user inputs; Recently, I have come across many user inputs with multiple white spaces.
Eg.
"My tests are working fine!"
Is there any way I can get rid of these white spaces at PHP level or MySQL level?
Clearly trim doesn't work here.
I was thinking of using Recursive function but not sure if there's an easy and fast way of doing this.
my code so far is as below:
function noWhiteSpaces($string) {
if (!empty($string)) {
$string = trim($string);
$new_str = str_replace(' ', ' ', $string);
} else {
return false;
}
return $new_str;
}
echo noWhiteSpaces("My tests are working fine here !");
If the input is actual whitespaces and you want to replace them with a single space, you could use a regular expression.
$stripped = preg_replace('/\s+/', ' ', $input);
\s means 'whitespace' character. + means one or more. So, this replaces every instance of one or more whitespace characters' in $input with a single space. See the preg_replace() docs, and a nice tutorial on regexes.
If you're not looking to replace real whitespace but rather stuff like , you could do the same, but not with \s. Use this instead:
$stripped = preg_replace('/( )+/', ' ', $input);
Note how the brackets enclose .
Related
I am working with a slug function and I dont fully understand some of it and was looking for some help on explaining.
My first question is about this line in my slug function $string = preg_replace('# +#', '-', $string); Now I understand that this replaces all spaces with a '-'. What I don't understand is what the + sign is in there for which comes after the white space in between the #.
Which leads to my next problem. I want a trim function that will get rid of spaces but only the spaces after they enter the value. For example someone accidentally entered "Arizona " with two spaces after the a and it destroyed the pages linked to Arizona.
So after all my rambling I basically want to figure out how I can use a trim to get rid of accidental spaces but still have the preg_replace insert '-' in between words.
ex.. "Sun City West " = "sun-city-west"
This is my full slug function-
function getSlug($string){
if(isset($string) && $string <> ""){
$string = strtolower($string);
//var_dump($string); echo "<br>";
$string = preg_replace('#[^\w ]+#', '', $string);
//var_dump($string); echo "<br>";
$string = preg_replace('# +#', '-', $string);
}
return $string;
}
You can try this:
function getSlug($string) {
return preg_replace('#\s+#', '-', trim($string));
}
It first trims extra spaces at the beginning and end of the string, and then replaces all the other with the - character.
Here your regex is:
#\s+#
which is:
# = regex delimiter
\s = any space character
+ = match the previous character or group one or more times
# = regex delimiter again
so the regex here means: "match any sequence of one or more whitespace character"
The + means at least one of the preceding character, so it matches one or more spaces. The # signs are one of the ways of marking the start and end of a regular expression's pattern block.
For a trim function, PHP handily provides trim() which removes all leading and trailing whitespace.
Ok so I am taking a string, querying a database and then must provide a URL back to the page. There are multiple special characters in the input and I am stripping all special characters and spaces out using the following code and replacing with HTML "%25" so that my legacy system correctly searches for the value needed. What I need to do however is cut down the number of "%25" that show up.
My current code would replace something like
"Hello. / there Wilbur" with "Hello%25%25%25%25there%25Wilbur"
but I would like it to return
"Hello%25there%25Wilbur"
replacing multiples of the "%25" with only one instance
$string = str_replace(' ', '-', $string); // Replaces all spaces with hyphens.
return preg_replace('/[^A-Za-z0-9]/', '%25', $string); // Replaces special chars.
Just add a + after selecting a non-alphanumeric character.
$string = "Hello. / there Wilbur";
$string = str_replace(' ', '-', $string);
// Just add a '+'. It will remove one or more consecutive instances of illegal
// characters with '%25'
return preg_replace('/[^A-Za-z0-9]+/', '%25', $string);
Sample input: Hello. / there Wilbur
Sample output: Hello%25there%25Wilbur
This will work:
while (strpos('%25%25', $str) !== false)
$str = str_replace('%25%25', '%25', $str);
Or using a regexp:
preg_replace('#((?:\%25){2,})#', '%25', $string_to_replace_in)
No looping using a while, so the more consecutive '%25', the faster preg_replace is against a while.
Cf PHP doc:
http://fr2.php.net/manual/en/function.preg-replace.php
I wrote this code to prepare a title for a link, but I think it is a bit bulky and am wondering if anyone with a better understanding of regex would be able to reduce the following function (by merging the relevant preg_replaces). I need it to strip all current hyphens, strip multiple spaces, ensure that it is solely alphanumeric apart from the space-replacing hyphen, replace all spaces with a single hyphen and ensure that the string doesn't start with a hyphen:
function prepareURLTitle($title)
{
return preg_replace("/\A-/", "", str_replace(" ", "-", preg_replace("/[^a-zA-Z0-9\s]/", "", preg_replace('/\s\s+/', ' ', preg_replace('/\s?-/', '', $title)))));
}
An example of input and it's output:
Input:
BRAND NEW - Gloves, 2 pack //Multiple spaces are in here but the blockquote won't allow me to display them
Output:
BRAND-NEW-Gloves-2-pack
trim(preg_replace('`[^a-z0-9]+`i','-',str_replace("'",'',$title)),'-')
I also replaced quotes with nothing, so strings like "The cat's meow" don't become "The-cat-s-meow".
function prepareURLTitle($title)
{
return preg_replace("[^A-Za-z0-9]+", "-", $title);
}
This should work. You need to replace multiple non-alphanumeric characters with a single "-".
preg_replace('~[^a-z\d]+~i','-',preg_replace('~^[^a-z\d]+(.*?)[^a-z\d]+$~i','$1',$title));
// or
preg_replace(array('~^[^a-z\d]+(.*?)[^a-z\d]+$~i','~[^a-z\d]+~i'),array('$1','-'),$title);
With an example…
$title = ' BRAND NEW - Gloves, 2 pack - ';
echo preg_replace(array('~^[^a-z\d]+(.*?)[^a-z\d]+$~i','~[^a-z\d]+~i'),array('$1','-'),$title);
will return
BRAND-NEW-Gloves-2-pack
function prepareURLTitle($title)
{
return preg_replace( "/[^a-zA-Z0-9]/", "-",str_replace("-", "", $title));
}
DEMO: http://codepad.org/lPSQQBys
OUTPUT:
BRAND-NEW--Gloves--2-pack
How can I remove a new line character from a string using PHP?
$string = str_replace(PHP_EOL, '', $string);
or
$string = str_replace(array("\n","\r"), '', $string);
$string = str_replace("\n", "", $string);
$string = str_replace("\r", "", $string);
To remove several new lines it's recommended to use a regular expression:
$my_string = trim(preg_replace('/\s\s+/', ' ', $my_string));
Better to use,
$string = str_replace(array("\n","\r\n","\r"), '', $string).
Because some line breaks remains as it is from textarea input.
Something a bit more functional (easy to use anywhere):
function strip_carriage_returns($string)
{
return str_replace(array("\n\r", "\n", "\r"), '', $string);
}
stripcslashes should suffice (removes \r\n etc.)
$str = stripcslashes($str);
Returns a string with backslashes stripped off. Recognizes C-like \n,
\r ..., octal and hexadecimal representation.
Try this out. It's working for me.
First remove n from the string (use double slash before n).
Then remove r from string like n
Code:
$string = str_replace("\\n", $string);
$string = str_replace("\\r", $string);
Let's see a performance test!
Things have changed since I last answered this question, so here's a little test I created. I compared the four most promising methods, preg_replace vs. strtr vs. str_replace, and strtr goes twice because it has a single character and an array-to-array mode.
You can run the test here:
https://deneskellner.com/stackoverflow-examples/1991198/
Results
251.84 ticks using preg_replace("/[\r\n]+/"," ",$text);
81.04 ticks using strtr($text,["\r"=>"","\n"=>""]);
11.65 ticks using str_replace($text,["\r","\n"],["",""])
4.65 ticks using strtr($text,"\r\n"," ")
(Note that it's a realtime test and server loads may change, so you'll probably get different figures.)
The preg_replace solution is noticeably slower, but that's okay. They do a different job and PHP has no prepared regex, so it's parsing the expression every single time. It's simply not fair to expect them to win.
On the other hand, in line 2-3, str_replace and strtr are doing almost the same job and they perform quite differently. They deal with arrays, and they do exactly what we told them - remove the newlines, replacing them with nothing.
The last one is a dirty trick: it replaces characters with characters, that is, newlines with spaces. It's even faster, and it makes sense because when you get rid of line breaks, you probably don't want to concatenate the word at the end of one line with the first word of the next. So it's not exactly what the OP described, but it's clearly the fastest. With long strings and many replacements, the difference will grow because character substitutions are linear by nature.
Verdict: str_replace wins in general
And if you can afford to have spaces instead of [\r\n], use strtr with characters. It works twice as fast in the average case and probably a lot faster when there are many short lines.
Use:
function removeP($text) {
$key = 0;
$newText = "";
while ($key < strlen($text)) {
if(ord($text[$key]) == 9 or
ord($text[$key]) == 10) {
//$newText .= '<br>'; // Uncomment this if you want <br> to replace that spacial characters;
}
else {
$newText .= $text[$key];
}
// echo $k . "'" . $t[$k] . "'=" . ord($t[$k]) . "<br>";
$key++;
}
return $newText;
}
$myvar = removeP("your string");
Note: Here I am not using PHP regex, but still you can remove the newline character.
This will remove all newline characters which are not removed from by preg_replace, str_replace or trim functions
I receive a string from a database query, then I remove all HTML tags, carriage returns and newlines before I put it in a CSV file. Only thing is, I can't find a way to remove the excess white space from between the strings.
What would be the best way to remove the inner whitespace characters?
Not sure exactly what you want but here are two situations:
If you are just dealing with excess whitespace on the beginning or end of the string you can use trim(), ltrim() or rtrim() to remove it.
If you are dealing with extra spaces within a string consider a preg_replace of multiple whitespaces " "* with a single whitespace " ".
Example:
$foo = preg_replace('/\s+/', ' ', $foo);
$str = str_replace(' ','',$str);
Or, replace with underscore, & nbsp; etc etc.
none of other examples worked for me, so I've used this one:
trim(preg_replace('/[\t\n\r\s]+/', ' ', $text_to_clean_up))
this replaces all tabs, new lines, double spaces etc to simple 1 space.
$str = trim(preg_replace('/\s+/',' ', $str));
The above line of code will remove extra spaces, as well as leading and trailing spaces.
If you want to replace only multiple spaces in a string, for Example: "this string have lots of space . "
And you expect the answer to be
"this string have lots of space", you can use the following solution:
$strng = "this string have lots of space . ";
$strng = trim(preg_replace('/\s+/',' ', $strng));
echo $strng;
There are security flaws to using preg_replace(), if you get the payload from user input [or other untrusted sources]. PHP executes the regular expression with eval(). If the incoming string isn't properly sanitized, your application risks being subjected to code injection.
In my own application, instead of bothering sanitizing the input (and as I only deal with short strings), I instead made a slightly more processor intensive function, though which is secure, since it doesn't eval() anything.
function secureRip(string $str): string { /* Rips all whitespace securely. */
$arr = str_split($str, 1);
$retStr = '';
foreach ($arr as $char) {
$retStr .= trim($char);
}
return $retStr;
}
$str = preg_replace('/[\s]+/', ' ', $str);
You can use:
$str = trim(str_replace(" ", " ", $str));
This removes extra whitespaces from both sides of string and converts two spaces to one within the string. Note that this won't convert three or more spaces in a row to one!
Another way I can suggest is using implode and explode that is safer but totally not optimum!
$str = implode(" ", array_filter(explode(" ", $str)));
My suggestion is using a native for loop or using regex to do this kind of job.
To expand on Sandip’s answer, I had a bunch of strings showing up in the logs that were mis-coded in bit.ly. They meant to code just the URL but put a twitter handle and some other stuff after a space. It looked like this
? productID =26%20via%20#LFS
Normally, that would‘t be a problem, but I’m getting a lot of SQL injection attempts, so I redirect anything that isn’t a valid ID to a 404. I used the preg_replace method to make the invalid productID string into a valid productID.
$productID=preg_replace('/[\s]+.*/','',$productID);
I look for a space in the URL and then remove everything after it.
I wrote recently a simple function which removes excess white space from string without regular expression implode(' ', array_filter(explode(' ', $str))).
Laravel 9.7 intruduced the new Str::squish() method to remove extraneous whitespaces including extraneous white space between words: https://laravel.com/docs/9.x/helpers#method-str-squish
$str = "I am a PHP Developer";
$str_length = strlen($str);
$str_arr = str_split($str);
for ($i = 0; $i < $str_length; $i++) {
if (isset($str_arr[$i + 1]) && $str_arr[$i] == ' ' && $str_arr[$i] == $str_arr[$i + 1]) {
unset($str_arr[$i]);
}
else {
continue;
}
}
echo implode("", $str_arr);