This is to test version numbers. They need to contain only numbers, but can have multiple decimal points.
For example:
$a = '1.2.3';
is_numeric($a) returns false, and floatval($a) strips out the extra decimal sections, without returning a useful answer to the test.
Is there any PHP function that would do this?
You can use preg_match():
if(preg_match('~^([0-9]+(\.[0-9]+)*)$~', $string)) {
echo 'ok';
}
The regex pattern matches from the begin ^ to the end $ of the string and checks if it begins with a number and then contains only numbers - optionally separated by single dots - and ends with a number again.
You can use the strcspn function:
$q='1.2.3';
if (strcspn($q, '0123456789') != strlen($q))
echo "true";
else
echo "false";
Related
I have a user-input string with 2 comma-delimited integers.
Example (OK):
3,5
I want to reject any user input that contains leading 0's for either number.
Examples (Bad):
03,5
00005,3
05,003
Now what I could do is separate the two numbers into 2 separate string's and use ltrim on each one, then see if they have changed from before ltrim was executed:
$string = "03,5";
$string_arr = explode(",",$string);
$string_orig1 = $string_arr[0];
$string_orig2 = $string_arr[1];
$string_mod1 = ltrim($string_orig1, '0');
$string_mod2 = ltrim($string_orig2, '0');
if (($string_mod1 !== $string_orig1) || ($string_mod2 !== $string_orig2)){
// One of them had leading zeros!
}
..but this seems unnecessarily verbose. Is there a cleaner way to do this? Perhaps with preg_match?
You could shorten the code and check if the first character of each part is a zero:
$string = "03,5";
$string_arr = explode(",",$string);
if ($string_arr[0][0] === "0" || $string_arr[1][0] === "0") {
echo "not valid";
} else {
echo "valid";
}
Here is one approach using preg_match. We can try matching for the pattern:
\b0\d+
The \b would match either the start of the string, or a preceding comma separator.
If we find such a match, it means that we found one or more numbers in the CSV list (or a single number, if only one number present) which had a leading zero.
$input = "00005,3";
if (preg_match("/\b0\d+/", $input)) {
echo "no match";
}
You can do a simple check that if the first character is 0 (using [0]) or that ,0 exists in the string
if ( $string[0] == "0" || strpos($string, ",0") !== false ) {
// One of them had leading zeros!
}
All the current answers fail if any of the values are simply 0.
You can just convert to integer and back and compare the result.
$arr = explode(',', $input);
foreach($arr as $item) {
if( (str)intval($item) !== $item ) {
oh_noes();
}
}
However I am more curious as to why this check matters at all.
One way would be with /^([1-9]+),(\d+)/; a regex that checks the string starts with one or more non-zero digits, followed by a comma, then one or more digits.
preg_match('/^([1-9]+),(\d+)/', $input_line, $output_array);
This separates the digits into two groups and explicitly avoids leading zeros.
This can be seen on Regex101 here and PHPLiveRegex here.
I have a function which will return true if input is pure numeric or alphabate else it will return false. This function is working fine.
function checktype($a)
{
if (preg_match('/^\d+$/', $a)) { //check numeric (can use other numeric regex also like /^[0-9]+$/ etc)
$return = true;
} else if (preg_match('/^[a-zA-Z]+$/', $a)) { //check alphabates
$return = true;
} else { //others
$return = false;
}
return $return;
}
var_dump(checktype('abcdfekjh')); //bool(true)
var_dump(checktype('1324654')); //bool(true)
var_dump(checktype('1324654hkjhkjh'));//bool(false)
No I tried to optimized this function by removing conditions so I modified code to:
function checktype($a)
{
$return = (preg_match('/^\d+$/', $a) || preg_match('/^[a-zA-Z]+$/', $a)) ? true:false;
return $return;
}
var_dump(checktype('abcdfekjh')); //bool(true)
var_dump(checktype('1324654')); //bool(true)
var_dump(checktype('1324654hkjhkjh'));//bool(false)
Now in third step I tried to merge both regex in single regex so I can avoid two preg_match function and got stuck here:
function checktype($a)
{
return (preg_match('regex to check either numeric or alphabates', $a)) ? true:false;
}
I tried a lot of combinations since 2 days by using OR(!) operator using not operator(?!) but no success at all.
Below some reference website from which i pick expression and made some combinations:
http://regexlib.com/UserPatterns.aspx?authorid=26c277f9-61b2-4bf5-bb70-106880138842
http://www.rexegg.com/regex-conditionals.html
OR condition in Regex
Regex not operator (come to know about NOT operator)
https://www.google.co.in/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=regular+expression+not+condition (come to know about NOT operator)
So here main question is, is there any single regex pattern to check string contains pure numeric value or pure alphabates?
Note: Alternative solution can be check string is alphanumeric and then return true or false accordingly. Also php inbuilt function like is_numeric and is_string can be used, but I am more curious to know the single regex pattern to check weather string conains pure numeric digit or pure alphaba digits.
A one regex to check if a string is all ASCII digits or all ASCII letters is
'/^(?:\d+|[a-zA-Z]+)$/'
See regex demo
This regex has two things your regexps do not have:
a grouping construct (?:....)
an alternation operator |.
Explanation:
^ - start of string
(?:\d+ - one or more digits
| - or...
[a-zA-Z]+) - one or more ASCII letters
$ - end of string
If you need to make it Unicode-aware, use [\p{L}\p{M}] instead of [a-zA-Z] (and \p{N} instead of \d, but not necessary) and use the /u modifier:
'/^(?:\p{N}+|[\p{L}\p{M}]+)$/u'
And in case you want to really check that from the beginning to end, use
'/\A(?:\p{N}+|[\p{L}\p{M}]+)\z/u'
^^ ^^
or
'/^(?:\p{N}+|[\p{L}\p{M}]+)$/Du'
The $ without /D modifier does not match the string at its "very end", it also matches if there is a newline after it as the last character.
I tried to add extra security by removing special characters. I want to allow letters, numbers and ? = & only.
I tried:
if (strpos($_SERVER['REQUEST_URI'],'\'')) { echo 'true'; }
I cannot just simply put ' in between the '' as it breaks it so I tried adding the \ but it didn't work.
Is there a way to detect all the symbols in the url string or input field?
EDIT:
tried adding < simply into the list
if (preg_match('#[#*,!$\'\-;:<>~`^|\(\\)\\{\\}\\[\\]]#i', $_SERVER['REQUEST_URI']) || strpos($_SERVER['REQUEST_URI'],'script')) {
echo 'Cannot do that';
}
I tried adding ([\<])([^\>]{1,})*([\>]) into there but it didn't work.
I also tried adding a condition if strcmp($_SERVER['REQUEST_URI'], strip_tags($_SERVER['REQUEST_URI'])) != 0
and when i added into the url, it didn't do anything
Use preg_match to test for anything but the characters you want:
if (preg_match('#[^a-z0-9?=&]#i', $str)) { echo 'true'; }
Use preg_replace to remove them:
$str = preg_replace('#[^a-z0-9?=&]#i', '', $str);
If you just want to prohibit certain characters, use a regular expression that just matches those characters:
if (preg_match('#[\'\-;:~`]#i', $str)) { echo 'true'; }
You can fix that using double quotes as strings delimiter, try this
if (strpos($_SERVER['REQUEST_URI'],"'")) { echo 'true'; }
One thing that none of the posts addressed is why strpos didn't work for you. strpos can return two types. It can return an integer that is greater than or equal to zero. 0 being the first character. It can also return a boolean type false. To check if if strpos found a match it would have to have been written like this:
if (strpos($_SERVER['REQUEST_URI'],'\'') !== false) { echo 'true'; }
From the PHP Documentation The comparison $a !== $b operator works this way:
return TRUE if $a is not equal to $b, or they are not of the same type.
Information on strpos returning two types (boolean false or an integer) can be found in this PHP strpos Documentation. In particular:
Returns the position of where the needle exists relative to the beginning of the haystack string (independent of offset). Also note that string positions start at 0, and not 1.
Returns FALSE if the needle was not found.
So as you can see 0 and false are not the same thing which is why your test failed.
As for security and strings in PHP I recommend you look at this StackOverflow article for some opinions on the matter.
I have many headlines in my project like:
00.00.2014 - Headline Description e.t.c.
I want to check with php if the given strings contain the format 00.00.0000 - in front. The part after the - doesn't matter.
Can someone help me with something like:
$format = '00.00.0000 -';
if ($string MATCHES $format IN FRONT) {
// ...some code...
}
This should work:
if (preg_match("/^\d{2}\.\d{2}\.\d{4}\s\-\s.*$/", $string) === 1) {
// $string matches!
}
Explanation:
^ is "the beginning of the string"
\d is any digit (0, 1, 2, ..., 9)
{n} means "repeated n times"
\. is a dot
\s is a space
\- is a minus sign
. is "any single character"
* means "repeated 0 or more times`
$ means "end of the string"
I don't have a dev environment to test this out on but i'll give you some psuedocode:
I'm unsure of the context, but you can test this function on any given STRING:
Function:
Boolean hasCorrectFormat($myString){
//Here take the string and cut it into a char array.
$charArray = str_split($myString);
//This will give you a char array. Compare the first 12 elements of this
//array to see if they are correct. If its supposed to be number make
//sure it is, if its supposed to be a "." make sure it is..etc
//"00.00.0000 -" is 12 characters.
if(!isNumeric(charArray[0])){
return false;
}
else if(!isNumeric(charArray[1])){
return false;
}
else if(charArray[2] != "."){
return false;
}
//so on and so forth.....
else {return true}
}
Like i said i can't test this, and i can almost guarantee you this code wont run. This should give you the logic involved though.
Edit: also i wrote this assuming you dont literally mean "00.00.0000" but rather "xx.xx.xxxx" x being any number 0-9. If you need to make sure it is literally zeros then just cut your string to be the first ten chars and compare it.
Use the strpos function. Something like this:
if (strpos($string,'00.00.0000 -') !== true) {
//some code
}
$var = 3;
if ($cleanvar = preg_match('/^[0-9]{0,2}$/', $var))
{
echo $cleanvar; echo $var; exit();
}
else
. . .
Strange output. This is causing my cleanvar to echo 1 and var still echo's 3. Why is this happening? The point of this regex is to only match whole numbers, as 1 or 2 digits. e.g.( 1, 2, 4, 38, 24)
Is their an issue in my Regex? Or what is causing this odd behavior?
$cleanvar is just true or false. You're looking for a number between 0 and 2 digits in length (from the beginning to the end of the string, so no other characters are allowed).
EDIT: it returns 1 if matched, 0 if not.
See this for more information: http://us3.php.net/preg_match
$var should be followed by an array if you want it set. You might wish to change to {1,2} if matching >=1.
Your regex is correct, and it is matching correct. Just that preg_match returns 1 if you get a match and 0 if it doesn't. See the documentation.
If you are trying to validate an input value, you only need look at the return of preg_match. Using the + operator matches "one or more of the preceding element."
if (preg_match('/^[0-9]+$/', $var)) {
// we matched a number only, so we know $var is clean
} else {
}
If you need to extract a number from an input field, you can use capture groups:
if (preg_match('/([0-9]+)/', $var, $matches)) {
$num = $matches[1];
} else {
}
Note that this does not match the entire input, but will return on the first number it finds in the input $var.