I am trying to write a regular expression to allow numbers and only one hypen in the middle (cannot be at start or at the end)
say pattern: 02-04 , 02are acceptable but
pattern: -- or - or -02 or 04- or 02-04-06 are unacceptable
I tried something like this but this would allow - at the beginning and also allow multiple -
'/^[0-9 \-]+$/'
I am not that good with regex so a little explanation would be real helpful.
EDIT: Sorry to bug you again with this but I need the numbers to be of only 2 digits (123-346) should be considered invalid.
Try this one:
/^\d{1,2}(-\d{1,2})?$/
One or two digits, followed by, optionally, ( a hyphen followed by one or two digits)
Fairly easy:
^\d+(-\d+)?$
At least one (+) digit (\d), followed by an optional group containing a hyphen-minus (-), followed by at least one digit again.
For strings containing only that pattern the following should work
^(\d{2}-)?\d{2}$
A group of 2 digits followed by minus ending with a group of 2 digits without minus.
Related
I have a filename i need to validate using preg_match in PHP, but i dont know much about regex patterns to fix my issue.
The string i am trying to validate is
2 numbers (0-9), a comma, 2 numbers (0-9), a hyphen, 2 numbers (0-9), a comma, 2 numbers (0-9)
An example is 47,60-51,00
I have tried the following
(-)?[0-9]+((,|-)[0-9]+)*
and
^[0-9][0-9,-]-[0-9,-][0-9]$
But both seem to fail one way or another. Could someone help point me in the right direction
You want to match the comma as a separate match but adding it to a character class [0-9,-] it can also match a digit or -
To match that format in a more specific way, you could use this pattern with a quantifier {2} to repeat matching a digit and match the comma's and hyphen at the expected position.
^[0-9]{2},[0-9]{2}-[0-9]{2},[0-9]{2}$
Regex demo
If you want the match to start with an optional hyphen you could start the pattern with ^-?
Assuming I have a set of numbers (from 1 to 22) divided by some trivial delimiters (comma, point, space, etc). I need to make sure that this set of numbers does not contain any repetition of the same number. Examples:
1,14,22,3 // good
1,12,12,3 // not good
Is it possible to do via regular expression?
I know it's easy to do using just php, but I really wander how to make it work with regex.
Yes, you could achieve this through regex via negative looahead.
^(?!.*\b(\d+)\b.*\b\1\b)\d+(?:,\d+)+$
(?!.*\b(\d+)\b.*\b\1\b) Negative lookahead at the start asserts that the there wouldn't be a repeated number present in the match. \b(\d+)\b.*\b\1\b matches the repeated number.
\d+ matches one or more digits.
(?:,\d+)+ One or more occurances of , , one or more digits.
$ Asserts that we are at the end .
DEMO
OR
Regex for the numbers separated by space, dot, comma as delimiters.
^(?!.*\b(\d+)\b.*\b\1\b)\d+(?:([.\s,])\d+)(?:\2\d+)*$
(?:([.\s,])\d+) capturing group inside this non-capturing group helps us to check for following delimiters are of the same type. ie, the above regex won't match the strings like 2,3 5.6
DEMO
You can use this regex:
^(?!.*?(\b\d+)\W+\1\b)\d+(\W+\d+)*$
Negative lookahead (?!.*?(\b\d+)\W+\1\b) avoids the match when 2 similar numbers appear one after another separated by 1 or more non-word characters.
RegEx Demo
Here is the solution that fit my current need:
^(?>(?!\2\b|\3\b)(1\d{1}|2[0-2]{1}|\d{1}+)[,.; ]+)(?>(?!\1\b|\3\b)(1\d{1}|2[0-2]{1}|\d{1}+)[,.; ]+)(?>(?!\1\b|\2\b)(1\d{1}|2[0-2]{1}|\d{1}+))$
It returns all the sequences with unique numbers divided by one or more separator and also limit the number itself from 1 to 22, allowing only 3 numbers in the sequence.
See working example
Yet, it's not perfect, but work fine! Thanks a lot to everyone who gave me a hand on this!
I have a quick question about regex for PHP.
My code:
^(\d{0,4}?)\.(?=(\d{1,2}))$
doesn't seem to work, where it's supposed to capture an optional group of up to 4 digits, then look ahead and conditionally capture a period based on if it captures a group of 1-2 digits.
Does anyone know why this doesn't work?
That's not the right way to do it - nothing about your regex indicates that the . is optional.
Try:
^(\d{0,4})(?:\.(\d{1,2}))?$
This will match up to four digits, which may optionally be followed by a dot, then one or two digits. In any case, the two subpatterns will contain the groups of digits.
I am using some data which gives paths for google maps either as a path or a set of two latitudes and longitudes. I have stored both values as a BLOB in a mySql database, but I need to detect the values which are not paths when they come out in the result. In an attempt to do this, I have saved them in the BLOB in the following format:
array(lat,lng+lat,lng)
I am using preg_match to find these results, but i havent managed to get any to work. Here are the regex codes I have tried:
^[a]{1}[r]{2}[a]{1}[y]{1}[\(]{1}[1-9\.\,\+]{1*}[\)]{1}^
^[a]{1}[r]{2}[a]{1}[y]{1}[\(]{1}(\-?\d+(\.\d+)?),(\-?\d+(\.\d+)?)\+(\-?\d+(\.\d+)?),(\-?\d+(\.\d+)?)[\)]{1}^
Regex confuses me sometimes (as it is doing now). Can anyone help me out?
Edit:
The lat can be 2 digits followed by a decimal point and 8 more digits and the lng can be 3 digits can be 3 digits follwed by a decimal point and 8 more digits. Both can be positive or negative.
Here are some example lat lngs:
51.51160000,-0.12766000
-53.36442000,132.27519000
51.50628000,0.12699000
-51.50628000,-0.12699000
So a full match would look like:
array(51.51160000,-0.12766000+-53.36442000,132.27519000)
Further Edit
I am using the preg_match() php function to match the regex.
Here are some pointers for writing regex:
If you have a single possibility for a character, for example, the a in array, you can indeed write it as [a]; however, you can also write it as just a.
If you are looking to match exactly one of something, you can indeed write it as a{1}, however, you can also write it as just a.
Applying this lots, your example of ^[a]{1}[r]{2}[a]{1}[y]{1}[\(]{1}[1-9\.\,\+]{1*}[\)]{1}^ reduces to ^array\([1-9\.\,\+]{1*}\)^ - that's certainly an improvement!
Next, numbers may also include 0's, as well as 1-9. In fact, \d - any digit - is usually used instead of 1-9.
You are using ^ as the delimiter - usually that is /; I didn't recognize it at first. I'm not sure what you can use for the delimiter, so, just in case, I'll change it to the usual /.This makes the above regex /array\([\d\.\,\+]{1*}\)/.
To match one or more of a character or character set, use +, rather than {1*}. This makes your query /array\([\d\.\,\+]+\)/
Then, to collect the resulting numbers (assuming you want only the part between the brackets, put it in (non-escaped) brackets, thus: /array\(([\d\.\,\+]+)\)/ - you would then need to split them, first by +, then by ,. Alternatively, if there are exactly two lat,lng pairs, you might want: /array\(([\d\.]+),([\d\.]+)\+([\d\.]+),([\d\.]+)\)/ - this will return 4 values, one for each number; the additional stuff (+, ,) will already be removed, because it is not in (unescaped) brackets ().
Edit: If you want negative lats and longs (and why wouldn't you?) you will need \-? (a "literal -", rather than part of a range) in the appropriate places; the ? makes it optional (i.e. 0 or 1 dashes). For example, /array\((\-?[\d\.]+),(\-?[\d\.]+)\+(\-?[\d\.]+),(\-?[\d\.]+)\)/
You might also want to check out http://regexpal.com - you can put in a regex and a set of strings, and it will highlight what matches/doesn't match. You will need to exclude the delimiter / or ^.
Note that this is a little fast and loose; it would also match array(5,0+0,1...........). You can nail it down a little more, for example, by using (\-?\d*\.\d+)\) instead of (\-?[\d\.]+)\) for the numbers; that will match (0 or 1 literal -) followed by (0 or more digits) followed by (exactly one literal dot) followed by (1 or more digits).
This is the regex I made:
array\((-*\d+\.\d+),(-*\d+\.\d+)\+(-*\d+\.\d+),(-*\d+\.\d+)\)
This also breaks the four numbers into groups so you can get the individual numbers.
You will note the repeated pattern of
(-*\d+\.\d+)
Explanation:
-* means 0 or more matches of the - sign ( so - sign is optional)
\d+ means 1 or more matches of a number
\. means a literal period (decimal)
\d+ means 1 or more matches of a number
The whole thing is wrapped in brackets to make it a captured group.
I'm trying to devise a regex pattern (in PHP) which will allow for any alternation of two subpatterns. So if pattern A matches a group of three letters, and B matches a group of 2 numerals, all of these would be OK:
aaa
aaa66bbb
66
67abc
12abc34def56ghi78jkl
I don't mind which subpattern starts or ends the sequence, just that after the first match, the subpatterns must alternate. I'm totally stumped by this - any advice will be gratefully received!
Here's a general solution:
^(?:[a-z]{3}(?![a-z]{3})|[0-9]{2}(?![0-9]{2}))+$
It's a simple alternation--three letters or two digits--but the negative lookaheads ensure that the same alternative is never matched twice in a row. Here's a slightly more elegant solution just for PHP:
/^(?:([a-z]{3})(?!(?1))|([0-9]{2})(?!(?2)))+$/
Instead of typing the same subpatterns multiple times, you can put them capturing groups and use (?1), (?2), etc. to apply them again wherever else you want--in this case, in the lookaheads.
"/^(?:$A(?:$B$A)*$B?|$B(?:$A$B)*$A?)\$/"
will match either pattern A followed by however many alternating pattern B's and pattern A's, and maybe a final B...or a B followed by however many A-B pairs plus an A if it's there.
I've made this a string (and escaped the final $) cause you're going to have some interpolation to do. Make sure $A and $B are in some kind of grouping (like parentheses) if you want the ?'s to match the right thing. In your examples, $A might be '([a-zA-Z]{3})' and $B might be '(\d\d)'.
Note, if you want to match some number of the same letter or digit, or instances of the same set of letters or digits, you'll need to do some magic with backreferences -- probably named ones, since any numbered backreference will depend on the number of capture groups before the one you want (or between the one you want and where you are), but that number gets complicated if the subpatterns have parentheses in them.
Take a look at this (and check conditional subpatterns). I've personally never used them but seems to be what you're looking for.
/\b(?:(([a-z])\2\2)(?:(([0-9])\4)\1)*(?:([0-9])\5)?|(([0-9])\7)(?:(([a-z])\9\9)\6)*(?:([a-z])\10\10)?)\b/
or if you want to allow any non digit char in the group of three:
/\b(?:((\D)\2\2)(?:((\d)\4)\1)*(?:(\d)\5)?|((\d)\7)(?:((\D)\9\9)\6)*(?:(\D)\10\10)?)\b/
This will match any pattern that consists of two alternating groups one group consists of 3 times the same char and the other of 2 times the same digit.
This Regex will match
aaa
11
bbb22
33ccc
ddd44ddd
55eee55
fff66fff66
77ggg77ggg
But not
aaa11bbb