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})$/
Related
I am working on some very messy Excel sheets, and trying to use PHP to find clues..
I have a MySQL database with all formulas from an excel document, and as usual, the cellnames from the current sheet do not have a "sheetname!" in front of it. To make it searchable (and find dead-routes in the formulas) I like to replace all formulas in the database with their sheetname as prefix.
Example:
=+(sheet_factory_costs!A17/sheet_employees!D23)+T12+W12
The database contains the name of the current sheet, and I like to change the formula above with that sheetname (let's call it "sheet_turnover").
=+(sheet_factory_costs!A17 / sheet_employees!D23)+sheet_turnover!T12+sheet_turnover!W12
I try this in PHP with preg_replace, and I think I need the following rules:
Find one or two letters, directly followed by a number. This is always a cell-adress within formulas.
When there is a ! on the position before, there is already a sheetname. So I am only looking for the letters and numbers NOT starting with an exclamation point.
The problem seems to be that the ! is also a special sign within patterns. Even if I try to escape it, it does not work:
$newformula =
preg_replace('/(?<\!)[A-Z]{1,2}[0-9]/',
'lala',
$oldformula);
(lala is my temporary marker to see if it is selecting the right cell-adresses)
(and yes, the lala is only places over the first number, but that's no issue right now)
(and yes, all Excel $..$.. (permanent) markers have already been replaced. No need to build that in the formula)
Your negative lookbehind is corrupt, you need to define it as (?<!!). However, you also need to use either a word boundary before it, or a (?<![A-Z]) lookbehind to make sure you have no other letters before the [A-Z]{1,2}.
So, you may use
'~\b(?<!!)[A-Z]{1,2}[0-9]~'
See the regex demo. Replace with sheet_turnover!$0 where $0 is the whole match value.
Details
\b - a word boundary (it is necessary, or name!AA11 would still get matched)
(?<!!) - no ! immediately to the left of the current location
[A-Z]{1,2} - 1 or 2 letters
[0-9] - a digit.
Another approach is match and skip "wrong" contexts and then match and keep the "right" ones:
'~\w+![A-Z]{1,2}[0-9](*SKIP)(*F)|\b[A-Z]{1,2}[0-9]~'
See this regex demo.
Here, \w+![A-Z]{1,2}[0-9](*SKIP)(*F)| part matches 1 or more word chars, then 1 or 2 uppercase ASCII letters and then a digit, and (*SKIP)(*F) will omit the match and will make the engine proceed looking for matches after the end of the previous match.
Given a string (and its variations) such as:
-1234567890-filename.extension-0987654321-
filename.extension-0987654321-
-1234567890-filename.extension
filename.extension
How do I look for the first set of digits (if any), the filename.extension string and the final set of digits (if any)?
I am trying this /^(?:-(\d+)-)?(.*)(?:-(\d+)-)?$/ but it will return only two values, where the second is filename.extension-0987654321- when the final set of digits is provided.
Thank you
Try this Regex:
(^-[^-]+)|(^.*$)
Explaining on Regex101.
I have a php pull down that I select an item and delete
all files associated with it.
It works well if there was only 5 or 6. After I put the
first 4 to test and get it working I realized it could
take a very long time to enter in a couple hundred and
would blot the script.
Not knowing enough about for and while loops is there
anyone that might have a way to help?
There will never be more than one set deleted at a time.
Thanks in advance.
<?php
$workitem = $_POST["workitem"];
$workdirPAth = "/var/work.files/";
if($workitem == 'item1.php')
{
unlink("$workdirPath/page1.php");
unlink("$workdirPath/temp1.php");
unlink("$workdirPath/all1.php");
}
if($workitem == 'item2.php')
{
unlink("$workdirPath/page2.php");
unlink("$workdirPath/temp2.php");
unlink("$workdirPath/all2.php");
}
if($workitem == 'item3.php')
{
unlink("$workdirPath/page3.php");
unlink("$workdirPath/temp3.php");
unlink("$workdirPath/all3.php");
}
if($workitem == 'item4.php')
{
unlink("$workdirPath/page4.php");
unlink("$workdirPath/temp4.php");
unlink("$workdirPath/all3.php");
?>
Some simple pattern matching and substitution is all you need here.
First, the code:
1. if (preg_match('/^item(\d+)\.php$/', $workitem, $matches)) {
2. $number = $matches[1];
3. foreach(array('page','temp','all') as $base) {
4. unlink("$workdirPath/$base$number.php");
5. }
6. } else {
7. # unrecognized work item value; complain to user or whatever
8. }
The preg_match function takes a pattern, a string, and an array. If the string matches the pattern, the parts that match are stored in the array. The particular type of pattern is a *p*erl5-compatible *reg*ular expression, which is where the preg_ part of the name comes from.
Regular expressions are scary-looking to the uninitiated, but they're a handy way to scan a string and get some values out of it. Most characters just represent themselves; the string "foo" matches the regular expression /foo/. But some characters have special meanings that let you make more general patterns to match a whole set of strings where you don't have to know ahead of time exactly what's in them.
The /s just mark the beginning and end of the actual regular expression; they're there because you can stick additional modifier flags inside the string along with the expression itself.
The ^and $ arepresent the beginning and end of the string. "/foo/" matches "foo", but also "foobar", "bunnyfoofoo", and so on - any string that contains "foo" will match. But /^foo$/ matches only "foo" exactly.
\d means "any digit". + means "one or more of that last thing". So \d+ means "one or more digits".
The period (.) is special; it matches any character at all. Since we want a literal period, we have to escape it with a backslash; \. just matches a period.
So our regular expression is '/^item\d+\.php$/', which will match any itemnumber.php filename. But that's not quite enough. The preg_match function is basically a binary test: does the string match the pattern or not, yes or no? In this case, it's not enough to just say "yup, the string is valid"; we need to know which items specifically the user specified. That's what capture groups are for. We use parentheses to say "remember what matched this part", and provide an array name that gets filled with those remembrances.
The part of the string that matches the whole regular expression (which may not be the whole string, if the regular expression isn't anchored with ^...$ like this one is) is always put in element 0 of the array. If you use parentheses in the regular expression, then the part of the string that matches the part of the regular expression inside the first pair of parentheses is stored in element 1 of the array; if there's a second set of parentheses, the matching part of the string goes in element 2 of the array, and so on.
So we put parentheses around our number ((\d+)) and then the actual number will be remembered in element 1 of our $matches array.
Great, we have a number. Now we just need to use it to build up the filenames we want to delete.
In each case, we want to delete three files: page$n.php, temp$n.php, and all$n.php, where $n is the number we extracted above. We could just put three unlink calls, but since they're all so similar, we can use a loop instead.
Take the different prefixes that are the same no matter the number, and make an array out of them. Then loop over that array. In the body of the loop, the variable $base will contain whichever element of the array it's currently on. Stick that between the $workdirPath prefix and the $number we got from the match, append .php, and that's your file. unlink it and go back to the top of the loop to grab the next one.
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 am trying to create a PHP REGEX that will match if two words appear next to each other with ANY number of spaces between them.
For example, match "Daniel Baylis" (3 spaces between 'Daniel' and 'Baylis'). I tried with this but it doesn't seem to work:
"/DANIEL[ ]{1,5}BAYLIS/" (this was to check up to 5 spaces which the most I expect in the data)
and
"/DANIEL[ ]{*}BAYLIS/"
I need to extract names from within larger bodies of text and names can appear anywhere within that text. User input error is what creates the multiple spaces.
Thanks all! - Dan
/DANIEL[ ]+BAYLIS/ should do... + will glob one or more occurence of the previous character(-class), in this case, litteral space.
Also, assuming you want to match regardless of the case, you'll need to adjust your regex to be case-insensitive, which I'm not sure how to do in PHP (it depends on which flavor of regex you use... Long time since I last touched that...)