I am trying to write a function that filteres everything from an input to only letters and the symbol "-". I want that symbol since the input contains names, and someone may be called Jean-Paul, this is my current code:
if(!preg_match('/^\[a-zA-Z]+$/',$string)) {
// Containing something other than a-z and A-Z
}
$string = 'Jean-Paul'; now gives that the string contains illegal characters, but how can I do so that it accepts "-" ?
if (!preg_match('/^[A-Z-]+$/i', $string)) {
// Contains something other than A-Z (case-insensitive) or -
}
A - is treated as a literal dash inside a character class if it's the first or last character there.
Be aware that "Jean-Rémy" will still fail. Are you sure you want to restrict yourself to ASCII letters?
If by "filter" you mean delete unwanted characters, then use
$s = preg_replace("/[^a-z-]/i", "", $s);
or
$s = preg_replace("/[^a-z-]/i", "", iconv('UTF-8', 'ASCII//TRANSLIT//IGNORE', $s));
Related
I'm working with text content in UTF8 encoding stored in variable $title.
Using preg_replace, how do I append an extra space if the $title string is ending with:
upper/lower case character
digit
symbol, eg. ? or !
This should do the trick:
preg_replace('/^(.*[\w?!])$/', "$1 ", $string);
In essence what it does is if the string ends in one of your unwanted characters it appends a single space.
If the string doesn't match the pattern, then preg_replace() returns the original string - so you're still good.
If you need to expand your list of unwanted endings you can just add them into the character block [\w?!]
Using a positive lookbehind before the end of the line.
And replace with a space.
$title = preg_replace('/(?<=[A-Za-z0-9?!])$/',' ', $title);
Try it here
You may want to try this Pattern Matching below to see if that does it for you.
<?php
// THE REGEX BELOW MATCHES THE ENDING LOWER & UPPER-CASED CHARACTERS, DIGITS
// AND SYMBOLS LIKE "?" AND "!" AND EVEN A DOT "."
// HOWEVER YOU CAN IMPROVISE ON YOUR OWN
$rxPattern = "#([\!\?a-zA-Z0-9\.])$#";
$title = "What is your name?";
var_dump($title);
// AND HERE, YOU APPEND A SINGLE SPACE AFTER THE MATCHED STRING
$title = preg_replace($rxPattern, "$1 ", $title);
var_dump($title);
// THE FIRST var_dump($title) PRODUCES:
// 'What is your name?' (length=18)
// AND THE SECOND var_dump($title) PRODUCES
// 'What is your name? ' (length=19) <== NOTICE THE LENGTH FROM ADDED SPACE.
You may test it out HERE.
Cheers...
You need
$title=preg_replace("/.*[\w?!]$/", "\\0 ", $title);
I am trying to verify in PHP with preg_match that an input string contains only "a-z, A-Z, -, _ ,0-9" characters. If it contains just these, then validate.
I tried to search on google but I could not find anything usefull.
Can anybody help?
Thank you !
Use the pattern '/^[A-Za-z0-9_-]*$/', if an empty string is also valid. Otherwise '/^[A-Za-z0-9_-]+$/'
So:
$yourString = "blahblah";
if (preg_match('/^[A-Za-z0-9_-]*$/', $yourString)) {
#your string is good
}
Also, note that you want to put a '-' last in the character class as part of the character class, that way it is read as a literal '-' and not the dash between two characters such as the hyphen between A-Z.
$data = 'abc123-_';
echo preg_match('/^[\w|\-]+$/', $data); //match and output 1
$data = 'abc..';
echo preg_match('/^[\w|\-]+$/', $data); //not match and output 0
You can use preg_replace($pattern, $replacement, $subject):
if (preg_replace('/[A-Za-z0-9\-\_]/', '', $string)) {
echo "Detect non valid character inside the string";
}
The idea is to remove any valid chars, if the result is NOT empty do the code.
I'm making a form that asks for the user's first and last name, and I don't want them entering
$heil4
I would like them to enter
Sheila
I know how to filter out everything except letters, but I'm aware that some names can have
Sheila-McDonald
So how would I remove everything from a string apart from letters and a hyphen?
Simply use
$s = preg_replace("/[^a-z-]/i", "", $s);
or if you want to convert some non-ascii characters to ascii, such as Jean-Rémy to Jean-Remy, then use
$s = preg_replace("/[^a-z-]/i", "", iconv('UTF-8', 'ASCII//TRANSLIT//IGNORE', $s));
Instead of replacing with nothing, have some fun. that way a name that consists mainly of numbers you can decode ;p
$name = '$h3il4-McD0nald';
$find = array(0,1,3,4,5,6,7,'$');
$replace = array('o','l','e','a','s','g','t','s');
$name = str_replace($find,$replace,$name);
//Sheila-McDonald
echo ucfirst(preg_replace('/[^a-z-]/i', '', $name));
$new = preg_replace('#[^A-Z-]#iu', '', $data);
but instead of removing letters (and thus modifying user's input) better validate it
and show an error if the input is not valid. This way the user will know that what he had entered is exactly the value you have
if(!preg_match('#[A-Z-]#iu', $data)) echo 'invalid';
Use this to strip out all non alpha-numeric characters, not including non latin characters, and prescribed punctuation.
$strtochange= preg_replace("/[^\s\p{Pd}a-zA-ZÀ-ÿ]/",'',$strtochange);
Note: this will turn $heil4 into heil.
I know this question has been asked several times for sure, but I have my problems with regular expressions... So here is the (simple) thing I want to do in PHP:
I want to make a function which replaces unwanted characters of strings. Accepted characters should be:
a-z A-Z 0-9 _ - + ( ) { } # äöü ÄÖÜ space
I want all other characters to change to a "_". Here is some sample code, but I don't know what to fill in for the ?????:
<?php
// sample strings
$string1 = 'abd92 s_öse';
$string2 = 'ab! sd$ls_o';
// Replace unwanted chars in string by _
$string1 = preg_replace(?????, '_', $string1);
$string2 = preg_replace(?????, '_', $string2);
?>
Output should be:
$string1: abd92 s_öse (the same)
$string2: ab_ sd_ls_o
I was able to make it work for a-z, 0-9 but it would be nice to allow those additional characters, especially äöü. Thanks for your input!
To allow only the exact characters you described:
$str = preg_replace("/[^a-zA-Z0-9_+(){}#äöüÄÖÜ -]/", "_", $str);
To allow all whitespace, not just the (space) character:
$str = preg_replace("/[^a-zA-Z0-9_+(){}#äöüÄÖÜ\s-]/", "_", $str);
To allow letters from different alphabets -- not just the specific ones you mentioned, but also things like Russian and Greek, or other types of accent marks:
$str = preg_replace("/[^\w+(){}#\s-]/", "_", $str);
If I were you, I'd go with the last one. Not only is it shorter and easier to read, but it's less restrictive, and there's no particular advantage to blocking stuff like и if äöüÄÖÜ are all fine.
Replace [^a-zA-Z0-9_\-+(){}#äöüÄÖÜ ] with _.
$string1 = preg_replace('/[^a-zA-Z0-9_\-+(){}#äöüÄÖÜ ]/', '_', $string1);
This replaces any characters except the ones after ^ in the [character set]
Edit: escaped the - dash.
I've got text from which I want to remove all characters that ARE NOT the following.
desired_characters =
0123456789!&',-./abcdefghijklmnopqrstuvwxyz\n
The last is a \n (newline) that I do want to keep.
To match all characters except the listed ones, use an inverted character set [^…]:
$chars = "0123456789!&',-./abcdefghijklmnopqrstuvwxyz\n";
$pattern = "/[^".preg_quote($chars, "/")."]/";
Here preg_quote is used to escape certain special characters so that they are interpreted as literal characters.
You could also use character ranges to express the listed characters:
$pattern = "/[^0-9!&',-.\\/a-z\n]/";
In this case it doesn’t matter if the literal - in ,-. is escaped or not. Because ,-. is interpreted as character range from , (0x2C) to . (0x2E) that already contains the - (0x2D) in between.
Then you can remove those characters that are matched with preg_replace:
$output = preg_replace($pattern, "", $str);
$string = 'This is anexample $tring! :)';
$string = preg_replace('/[^0-9!&\',\-.\/a-z\n]/', '', $string);
echo $string; // hisisanexampletring!
^ This is case sensitive, hence the capital T is removed from the string. To allow capital letters as well, $string = preg_replace('/[^0-9!&\',\-.\/A-Za-z\n]/', '', $string)