How can I get, into an array, all occurrences of this pattern 4321[5-9][7-9]{6} but excluding, for example, the occurrences where there is a digit immediately before the value, or immediately after it?
For instance, 43217999999 should be valid but 143217999999 (note the number 1 at the beginning) should not be valid.
As the first example, 432179999991 shouldn't be valid because of the 1 that it has in the end.
The added difficulty, at least for me, is that I have to parse this in whatever position I can find it inside a string.
The string looks like this, literally:
43217999997 / 543217999999 // 43217999998 _ 43217999999a43216999999-43216999999 arandomword 432159999997
As you would be able to note, it has no standard way of separating the values (I marked in bold the values that would make it invalid, so I shouldn't match those)
My idea right now is something like this:
(\D+|^)(4321[5-9][7-9]{6})(\D+|$)
(\D+|^) meaning that I expect in that position the start of the string or at least one non-digit and (\D+|$) meaning that I expect there the end of the string or at least one non-digit.
That obviously doesn't do what I picture in my head.
I also tried do it in two steps, first:
preg_match_all("/\D+4321[5-9][7-9]{6}\D+|4321[5-9][7-9]{6}\D+|4321[5-9][7-9]{6}$/", $input, $outputArray);
and then:
for($cont = 0; $cont < count($outputArray); $cont++) {
preg_match("/4321[5-9][7-9]{6}/", $outputArray[0][$cont], $outputArray2[]);
}
so I can print
echo "<pre>" . print_r($outputArray2, true) . "</pre>";
but that doesn't let me exclude the ones that have a number before the start of the value (5432157999999 for example), and then, I am not making any progress with my idea.
Thanks in advance for any help.
If you literally want to check if there is no digit before or after the match you can use negative look ahead and look behind.
(?![0-9]) at the end means: "is not followed by 0-9"
(?<![0-9]) at the start means: "is not preceded by 0-9"
See this example https://regex101.com/r/6xbmJk/1
I use the following function to find the nth character in a string which works well. However there is one exception, lets say its a comma for this purpose, what i need to alter about this is that if the coma is within ( and ) then it shouldnt count that
function strposnth($haystack, $needle, $nth=1, $insenstive=0)
{
//if its case insenstive, convert strings into lower case
if ($insenstive) {
$haystack=strtolower($haystack);
$needle=strtolower($needle);
}
//count number of occurances
$count=substr_count($haystack,$needle);
//first check if the needle exists in the haystack, return false if it does not
//also check if asked nth is within the count, return false if it doesnt
if ($count<1 || $nth > $count) return false;
//run a loop to nth number of occurrence
//start $pos from -1, cause we are adding 1 into it while searching
//so the very first iteration will be 0
for($i=0,$pos=0,$len=0;$i<$nth;$i++)
{
//get the position of needle in haystack
//provide starting point 0 for first time ($pos=0, $len=0)
//provide starting point as position + length of needle for next time
$pos=strpos($haystack,$needle,$pos+$len);
//check the length of needle to specify in strpos
//do this only first time
if ($i==0) $len=strlen($needle);
}
//return the number
return $pos;
}
So ive got the regex working that only captures the comma when outside of () which is:
'/,(?=[^)]*(?:[(]|$))/'
and you can see a live example working here:
http://regex101.com/r/xE4jP8
but im not sure how to make it work within the strpos loop, i know what i need to do, tell it the needle has this regex exception but i am not sure how to make it work. Maybe i should ditch the function and use another method?
Just to mention my end result i want is to split the string after every 6 commas before the next string starts, example:
rttr,ertrret,ertret(yes,no),eteert,ert ert,rtrter,0 rttr,ert(yes,no)rret,ert ret,eteert,ertert,rtrter,1 rttr,ertrret,ert ret,eteert,ertert,rtrter,0 rttr,ertrret,ert ret,eteert,ertert,rtrter,2 rttr,ert(white,black)rret,ert ret,eteert,ertert,rtrter,0 rttr,ertrret,ert ret,eteert,ertert,rtrter,0 rttr,ertrret,ert ret,et(blue,green)eert,ertert,rtrter,1
Note that there is always a 1 digit number (1-3) and a space after the 6th comma before the next part of the string begins but i cant really rely on that as its possible earlier in the string this pattern could happen so i can always rely on the fact ill need to split the string after the first digit and space after the 6th comma. So i want to split the string directly after this.
For example the above string would be split like this:
rttr,ertrret,ertret(yes,no),eteert,ert ert,rtrter,0
rttr,ert(yes,no)rret,ert ret,eteert,ertert,rtrter,1
rttr,ertrret,ert ret,eteert,ertert,rtrter,0
rttr,ertrret,ert ret,eteert,ertert,rtrter,2
rttr,ert(white,black)rret,ert ret,eteert,ertert,rtrter,0
rttr,ertrret,ert ret,eteert,ertert,rtrter,0
rttr,ertrret,ert ret,et(blue,green)eert,ertert,rtrter,1
I can do that myself pretty easily if i know how to get the position of the character then i can use substr to split it but an easier way might be preg_split but im not sure how that would work until i figure this part out
I hope i wasnt too confusing in explaining, i bet i was :)
For these kind of nesting problems regex usually is not the right tool. However, when the problem is actually not that complicated, as yours seems to be, regex will do just fine.
Try this:
(?:^|,)((?:[^,(]*(?:\([^)]*\))?)*)
^ start the search with a comma or the start of the string
^ start non capture group
^ search until comma or open parenthesis
^ if parenthesis found then capture until
^ end of parenthesis
^ end of capture group repeat if necessary
See it in action: http://regex101.com/r/eS0cX4
As you can see this will capture everything between the comma's outside of the parenthesis. If you get all these matches into an array using preg_match_all you can split it any which way you like.
I'm trying to match a number that may consist of [1-4], with a length of {1,1}.
I've tried multiple variations of the following, which won't work:
/^string\-(\d{1,1})[1-4]$/
Any guidelines? Thanks!
You should just use:
/^string-[1-4]$/
Match the start of the string followed by the word "string-", followed by a single number, 1 to 4 and the end of the string. This will match only this string and nothing else.
If this is part of a larger string and all you want is the one part you can use something like:
/string-[1-4]\b/
which matches pretty much the same as above just as part of a larger string.
You can (in either option) also wrap the character class ([1-4]) in parentheses to get that as a separate part of the matches array (when using preg_match/preg_match_all).
This is not hard:
/^string-([1-4]{1})$/
I have a string that contains 5 words. In the string one of the words is a Ham Radio Call Sign and can be anyone of the thousands of call signs in the US. In order to extract the Call Sign from the string I need to utilize the below pattern. The Call Sign I need to extract can be in any of the 5 positions in the string. The number is never the first character and the number is never the last character. The string is actually put together from an Array since it is originally read from a text file.
$string = $word[1] $word[2] $word[3] etc....
So the search can be either done on the whole string or each piece of the array.
Patterns:
1 Number and 3 Letters Example: AB4C A4BC
1 Number and 4 Letters Example: A4BCD
1 Number and 5 Letters Example: AB4CDE
I have tried everything I can think of and search till I cant search no more. I am sure I am over thinking this.
A two-step regular expression like this would do it:
$str = "hello A4AB there BC5AD";
$signs = array();
preg_match_all('/[A-Z][A-Z\d]{1,3}[A-Z]/', $str, $possible_signs);
foreach($possible_signs[0] as $possible_sign)
if (preg_match('/^\D+\d\D+$/', $possible_sign))
array_push($signs, $possible_sign);
print_r($signs); //Array ([0] => A4AB [1] => BC5AD)
Explanation
This is a regular expression approach, using two patterns. I don't think it could be done with one and still satisfy the exact requirements of the matching rules.
The first pattern enforces the following requirements:
substring starts and ends with a capital letter
substring contains only other capital letters or numbers between the first and last letter
substring is, overall, not more than 6 characters long
What I can't do in that same pattern, for complex REGEX reasons I won't go into (unless someone knows a way and can correct me), is enforce that only one number is contained.
#jeroen's answer does enforce this in a single pattern, but in turn does not enforce the correct length of the substring. Either way, we need a second pattern.
So after grabbing the initial matches, we loop over the results. We then apply each to a second pattern that enforces simply that there is only one number in the substring.
If so, we green-light the substring and it's added to the $signs array.
Hope this helps.
It depends on what the other words can contain, but you could use a regular expression like:
#\b[a-z]+\d[a-z]+\b#i
^ case insensitive
^^ a word boundary
^^^^^^ One or more letters
^^ One number
You can make it more restrictive by using {1,3} instead of + for the letters so that you have a sequence of 1 to 3 letters.
The complete expression would be something like:
$success = preg_match('#\b[a-z]+\d[a-z]+\b#i', $input_string, $matches);
where $matches[0] will contain the matched value, see the manual.
I have a PHP array of strings. The strings are supposed to represent PIN codes which are of 6 digits like:
560095
Having a space after the first 3 digits is also considered valid e.g. 560 095.
Not all array elements are valid. I want to filter out all invalid PIN codes.
Yes you can make use of regex for this.
PHP has a function called preg_grep to which you pass your regular expression and it returns a new array with entries from the input array that match the pattern.
$new_array = preg_grep('/^\d{3} ?\d{3}$/',$array);
Explanation of the regex:
^ - Start anchor
\d{3} - 3 digits. Same as [0-9][0-9][0-9]
? - optional space (there is a space before ?)
If you want to allow any number of any whitespace between the groups
you can use \s* instead
\d{3} - 3 digits
$ - End anchor
Yes, you can use a regular expression to make sure there are 6 digits with or without a space.
A neat tool for playing with regular expressions is RegExr... here's what RegEx I came up with:
^[0-9]{3}\s?[0-9]{3}$
It matches the beginning of the string ^, then any three numbers [0-9]{3} followed by an optional space \s? followed by another three numbers [0-9]{3}, followed by the end of the string $.
Passing the array into the PHP function preg_grep along with the Regex will return a new array with only matching indeces.
If you just want to iterate over the valid responses (loop over them), you could always use a RegexIterator:
$regex = '/^\d{3}\s?\d{3}$/';
$it = new RegexIterator(new ArrayIterator($array), $regex);
foreach ($it as $valid) {
//Only matching items will be looped over, non-matching will be skipped
}
It has the benefit of not copying the entire array (it computes the next one when you want it). So it's much more memory efficient than doing something with preg_grep for large arrays. But it also will be slower if you iterate multiple times (but for a single iteration it should be faster due to the memory usage).
If you want to get an array of the valid PIN codes, use codaddict's answer.
You could also, at the same time as filtering only valid PINs, remove the optional space character so that all PINs become 6 digits by using preg_filter:
$new_array = preg_filter('/^(\d{3}) ?(\d{3})$/D', '$1$2', $array);
The best answer might depend on your situation, but if you wanted to do a simple and low cost check first...
$item = str_replace( " ", "", $var );
if ( strlen( $item ) !== 6 ){
echo 'fail early';
}
Following that, you could equally go on and do some type checking - as long as valid numbers did not start with a 0 in which case is might be more difficult.
If you don't fail early, then go on with the regex solutions already posted.