I would like to match String that contains letters and numbers WITHOUT space
I tried ^[a-zA-Z+d*]*$ but it matches String that have only letters
This is what it should do :
Nope
Nope 2
MatchPlease123
If you want to try in live:
http://rubular.com/r/pFMkk9ATc0
Thank you
You may use
/^(?=[^a-zA-Z]*[a-zA-Z])(?=[^0-9]*[0-9])[a-zA-Z0-9]*$/
See the regex demo (a bit modified since the input is a multiline string).
Details:
^ - start of a string
(?=[^a-zA-Z]*[a-zA-Z]) - a positive lookahead requiring that there must be at least one ASCII letter after any 0+ chars other than ASCII letters
(?=[^0-9]*[0-9]) - a positive lookahead requiring that there must be at least one ASCII digit after any 0+ chars other than ASCII digits
[a-zA-Z0-9]* - 0+ ASCII letters or digits
$ - end of string.
I think this simplest one will also be helpful
Regex demo
Regex: ^(?=.*\d)(?=.*[a-zA-Z])[a-zA-Z\d]+$
1. ^ start of string.
2. (?=.*\d) positive look ahead for digit.
3. (?=.*[a-zA-Z]) positive look alphabets.
4. [a-zA-Z\d]+ match all digits A-Z and a-z
5. $ end of string.
Related
I have to match a string that is 3-6 characters long, contains at least one letter, but can have letters, numbers and only 1 "-".
The "-" must not be at the start or at the beginning.
Match:
string
str-ng
st-ng
s1-1g
st-1g
Do not match:
strings
-string
string-
st--ng
s-tn-g
1111
st
The closest I've gotten is this:
^((?!-.*-)[0-9A-Z]{3,6})$
But this divides the regex match with - So it matches s-tri but not st-ri because there aren't 3 chars at each end
Maybe you can use:
^(?=.*[a-z])(?!-|.*-$|.*-.*-)[a-z\d-]{3,6}$
See the online demo
^ - Start string anchor.
(?=.*[a-z]) - Positive lookahead to make sure there is at least one letter.
(?!-|.*-$|.*-.*-) - Negative lookahead to prevent a hyphen at the beginning or at the end or multiple.
[a-z\d-]{3,6} - Three to six times a character from the give class.
$ - End string anchor.
Note that I used the case-insensitive flag.
You can use
^(?=.{3,6}$)(?=[^a-zA-Z]*[A-Za-z])[0-9a-zA-Z]+(?:-[0-9a-zA-Z]+)?$
See the regex demo. Details:
^ - start of string
(?=.{3,6}$) - string must contain three to six chars other than line break chars
(?=[^a-zA-Z]*[A-Za-z]) - there must be at least one ASCII letter in the string
[0-9a-zA-Z]+ - one or more alphanumeric ASCII chars
(?:-[0-9a-zA-Z]+)? - an optional sequence of - and then one or more alphanumeric ASCII chars
$ - end of string.
Looking at the pattern that you tried, you meant to exclude the match when there are 2 hyphens present using the negative lookahead.
Also this part [0-9A-Z]{3,6} does not match a hyphen.
Reading
The "-" must not be at the start or at the beginning.
You might do that using
^(?![^\n-]*-[^\n-]*-)(?=[^a-zA-Z\n]*[a-zA-Z])[a-zA-Z0-9][a-zA-Z0-9-]{2,5}$
Regex demo
If you meant also no - at the end:
^(?![^\n-]*-[^\n-]*-)(?=[^a-zA-Z\n]*[a-zA-Z])[a-zA-Z0-9][a-zA-Z0-9-]{1,4}[a-zA-Z0-9]$
Explanation
^ Start of string
(?![^\n-]*-[^\n-]*-) Assert not 2 times -
(?=[^a-zA-Z\n]*[a-zA-Z]) Assert a char a-zA-Z
[a-zA-Z0-9] Match One of the listed without -
[a-zA-Z0-9-]{1,4} Repeat 1-4 times any of the listed including -
[a-zA-Z0-9] Match One of the listed without -
$ End of string
Regex demo
To match a dash-less checksum I can do something like:
\b[0-9a-z]{32}\b
However, I'm seeing some checksums that also have dashes, such as:
d3bd55bf-062f-473b-9417-935f62c4c98a
While this is probably a fixed size, 8, then 4, then 4, then 4, then 12, I was wondering if I could do a regex where the number of non-dash digits adds up to 32. I think the answer is no, but hopefully some regex wizard can come up with something.
Here is a starting point for some sample inputs: https://regex101.com/r/K0IMKe/1.
You can use
\b[0-9a-z](?:-?[0-9a-z]){31}\b
See the regex demo.
It matches
\b - a word boundary
[0-9a-z] - a digit or a lowercase ASCII letter
(?:-?[0-9a-z]){31} - thirty-one repetitions of an optional - followed with a single digit or a lowercase ASCII letter
\b - a word boundary.
If you do not mind having a trailing - if there is a word char after it, at the end of a match, you may also use
\b(?:[0-9a-z]-?){32}\b
See this regex demo. Here, (?:[0-9a-z]-?){32} will match thirty-two repetitions of a digit or lowercase ASCII letter followed with an optional hyphen.
If there can be multiple dashes, you can assert 32 to 36 chars using a positive lookahead.
^(?=[a-z0-9-]{32,36}$)[a-z0-9]+(?:-[a-z0-9]+)*$
^ Start of string
(?=[a-z0-9-]{32,36}$) Positive lookahead, assert what is at the right is 32 - 36 repetitions of the listed characters
[a-z0-9]+ Match 1+ times any of the listed
(?: Non capture group
-[a-z0-9]+ Match a - followed by 1+ times any of the listed (the string can not end with a hyphen)
)* Close the group and match 0+ times to also match the string without dashes
$ End of string
Regex demo
If you want to limit the amount of dashes to 0 -4 times, you can change the quantifier * to {0,4}+
^(?=[a-z0-9-]{32,36}$)[a-z0-9]+(?:-[a-z0-9]+){0,4}+$
Regex demo
I am trying to write a regular expresion that checks if a string starts with a number of digits (at least one), and then immediately ends with a single letter or a digit.
So:
29c is fine
29 is fine
2425315651252fsaw fails
24241jl.421c fails
c fails
The regex I have so far is (^\d+)([a-z]{1}|\d) which passes the 29, 20c, but also passes stuff like 29cdsd.
What am I doing wrong?
Your (^\d+)([a-z]{1}|\d) passes 29cdsd because it matches 1 or more digits at the start of the string followed with 1 letter or 1 digit, and allows anything right after.
Use
^[0-9]+[a-z0-9]?$
See regex demo
Details
^ - start of string
[0-9]+ - any 1 or more digits
[a-z0-9]? - 1 or 0 lowercase ASCII letters or digits
$ - end of string.
This should follow your rules exactly.
^\d+[a-z]?$
if "any number of digits" might be zero ^\d*\w$
You could add an anchor $ to assert the end of the line and you can omit the {1} part:
^(\d+)([a-z]|\d)$
In your regex you are matching a minimum of 2 characters .If you don't need the capturing groups, this could also be written as:
^\d+[a-z\d]$
Regex demo
That would match:
^ Assert the start of the string
\d+ Match 1+ digits
[a-z\d] A character class which matches a-z or a digit
$ Assert the end of the string
^ - start of string
\d* - any amount of digits, 0 or more
[a-zA-z] - a lowercase and uppercase ASCII letters.
$ - end of string
How can i write a regexp, that will check if string starts and ends with digits and in between contains only digits and comas? Comas must also be separated from each other with at least one digit. For the conditions above i have following regexp: ^\d(,?\d)*$ but i have following additional condition: All comma separated integers, that are composed by sequences of digits, must be different from each other. What would be the regexp that allows only this kind of strings?
Thank you
First of all, your regex contains unquantified \d, and that matches only single digits. You need to add + after \d to match 1 or more digits.
To avoid having duplicate values, you may use
^(?!.*\b(\d+)\b.*\b\1\b)\d+(?:,\d+)*$
^^^^^^^^^^^^^^^^^^^^^^^
See the regex demo
The (?!.*\b(\d+)\b.*\b\1\b) is a negative lookahead that will fail the match if after any 0+ chars other than line break chars, there is a group of digits that appear later in the string (after another 0+ chars other than line break chars) again.
Details
^ - start of string
(?!.*\b(\d+)\b.*\b\1\b) - a negative lookahead that fails the match if identical values appear in the text
\d+ - 1+ digits
(?:,\d+)* - zero or more occurrences of
, - a comma
\d+ - 1+ digits
$ - end of string.
I need to check if the string contains from 0 to 3 spaces and 16 digits. How can I do this ? All that I come up with is only for checking the sum
^[0-9- ]{16,19}$
You actually should use
^(?=(?:[^ ]* ){0,3}[^ ]*$)(?=(?:[^0-9]*[0-9]){16}[^0-9]*$)[0-9- ]+$
See the regex demo at regex101.com.
Alternatively, the first space checking positive lookahead may be replaced with a negative one with reverse logic:
^(?!(?:[^ ]* ){4})(?=(?:[^0-9]*[0-9]){16}[^0-9]*$)[0-9- ]+$
See another demo
Both the regexps are written with the principle of contrast in mind, so as to fail the regex quicker if the lookahead pattern does not match.
Details:
^ - start of string
(?!(?:[^ ]* ){4}) - a negative lookahead failing the match if there are 4 sequences immediately to the right of the current location, of:
[^ ]* - 0+ chars other than a space
- a space
(?=(?:[^0-9]*[0-9]){16}[^0-9]*$) - a positive lookahead requiring that the whole string should contain 16 sequences of 0+ non-digits ([^0-9]*) followed with 1 digit, and then 0+ chars other than a digit up to the end of the string
[0-9- ]+ - matches 1+ chars that are either digits, - or spaces
$ - end of string.
You can use this regex based on lookaheads:
^[0-9](?!(?:[0-9]* ){4})(?=(?: *[0-9]){15}$)[0-9- ]+[0-9]$
RegEx Demo
^[0-9] and [0-9]$ ensures we have only digits at start and end.
(?!(?:[0-9]* ){4}) is negative lookahead to disallow 4 spaces (thus allowing 0 to 3 whitespaces)
(?=(?: *[0-9]){16} *$) is positive lookahead to allow exactly 16 digits in the input surrounded by optional spaces.