I need to validate an IP range that is in format 000000000 to 255255255 without any delimiters between the 3 groups of numbers.
Each of the three groups that the final IP consists of should be 000 (yes, 0 padded) to 255.
As this is my 1st stackoverflow entry, please be lenient if I did not follow etiquette correctly.
^([01]\d{2}|2[0-4]\d|25[0-5]){3}$
Which breaks down in the following parts:
000-199
200-249
250-255
If you decide you want 4 octets instead of 3, just change the last {3} to {4}. Also, you should be aware of IPv6 too.
I would personally not use regex for this. I think it's easier to ensure that the string consists of 9 digits, split up the string into 3 groups of 3-digit numbers, and then check that each number is between 0 and 255, inclusive.
If you really insist on regex, then you could use something like this:
"([0-1][0-9][0-9]|2[0-4][0-9]|25[0-5]){3}"
The expression comprises an alternation of three terms: the first matches 000-199, the second 200-249, the third 250-255. The {3} requires the match exactly three times.
This is a pretty common question. Here is a nice intro page on regexps, that has this case as an example. It includes the periods, but you can edit those out easily enough.
for match exclusively a valid IP adress use
(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)){3}
instead of
([01]?[0-9][0-9]?|2[0-4][0-9]|25[0-5])(([01]?[0-9][0-9]?|2[0-4][0-9]|25[0-5])){3}
because many regex engine match the first possibility in the OR sequence
you can try your regex engine with : 10.48.0.200
\b\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\b
I use this RegEx for search all ip in code from my project
Related
I have two 1-6 digit numbers separated by a slash. I want these split up into groups of at most 3 digits, taking from the right.
For example:
0/1 -> [,0,,1]
1234/3 -> [1,234,,3]
12345/1234 -> [12,345,1,234]
123456/789123 -> [123,456,789,123]
I need to use a regular expression to do this because I want to do this for a location in NGINX. It's possible to do this with application logic but that is not the question due to performance.
Similar question which solves part of this was here using a negative lookahead: Regular expression to match last number in a string
What regex can achieve this split?
UPDATE:
This regex comes close to what I want (https://regex101.com/r/bQtNdK/3):
(?<prefix1>\d{0,3}?)(?<threes1>\d{0,3})\/(?<prefix2>\d{0,3}?)(?=\d)(?<threes2>\d{0,3})
It fails matching if the second number behind the slash is more than 3 digits long.
UPDATE2:
Now this regex works for most combinations (https://regex101.com/r/bQtNdK/5):
(?<prefix1>\d{0,3}?)(?<threes1>\d{1,3})\/(?<prefix2>\d{0,3})(?<threes2>\d{3})
I don't understand why this starts to fail if I use the same regex for prefix2/threes2 like prefix1/threes1 (i.e. make prefix2 also lazy). Any ideas how to solve this? So close...
I don't know that it's possible without the ability for the regex engine to remember all intermediate matches of a match group that matched an arbitrary number of times (.NET can do this, not sure what others). PCRE will apparently only remember the 'last' match for each group, other wise you could use something like this : (?<prefix1>\d{0,2})(?:(?<threes1>\d{3})*)\/(?<prefix2>\d{0,2})(?<threes2>\d{3})*\s
This regex seems to be correct now (regex101):
(?<prefix1>\d{0,3}?)(?<suffix1>\d{1,3})\/(?<prefix2>\d{0,3}?)(?<suffix2>\d{1,3})\/
So this is the regex I've made:
^(([01]?\d{1,2})|(2(([0-4]\d)|(5[0-5])))\.){3}(([01]?\d{1,2})|(2(([0-4]\d)|(5[0-5]))))$
I have used several sites to break it down and it seems that it should work, but it doesn't. The desired result is to match any IPv4 - four numbers between 0 and 255 delimited by dots.
As an example, 1.1.1.1 won't give you a match.
The purpose of this question is not to find out a regex for IPv4 address, but to find out why this one, which seems correct, is not.
The literal . is only part of the 200-255 section of the capture group: railroad diagram.
Here's (([01]?\d{1,2})|(2([0-4]\d)|(5[0-5]))\.) formatted differently to help you spot the reason:
(
([01]?\d{1,2})
|
(2([0-4]\d)|(5[0-5])) \.
)
You're matching 0-199 or 200-255 with a dot. The dot is conditional on matching 200-255.
Additionally, as #SebastianProske pointed out, 2([0-4]\d)|(5[0-5]) matches 200-249 or 50-55, not 200-255.
You can fix your regex by adding capturing groups, but ultimately I would recommend not reinventing the wheel and using A) a pre-existing regex solution or B) parse the IPv4 address by splitting on dots. The latter method being easier to read and understand.
to fix yours up, just account for the "decimal" after each of the first three groups:
((2[0-4]\d|25[0-5]|[01]?\d{1,2})\.){3}(2[0-4]\d|25[0-5]|[01]?\d{1,2})
(*note that I reversed the order of the 2xx vs 1xx tests as well - prefer SPECIAL|...|NORMAL, or more restrictive first, when using alternations like this)
see it in action
I am trying to get/make a regular expression but i can't figure it out. I am searching for an expression so that a user, who is filling a form, can't type 0 ore 1. So it has to start at least with 2. What is the expression for it?
Thanks a lot.
Thanks. But this is not 100% waterproof. As a user you can't fill 0 or 1 but you can't fill 10 or 11 or 101 either. So everything with a 0 or a 1 at the beginning. Is there a solution?
Thanks again.
here, this should accept any numbers starting with 2 or more:
[2-9][0-9]*
or
^[2-9][0-9]*$
if you are matching whole lines.
I understand you mean it begins with a digit from 2 to 9, but you should tell if it can contain else later.
for pure numbers:
[2-9][0-9]*
this forces the content be numeric ans start with a digit > 1.
Use:
[2-9][0-9]+
if more than one number is mandatory,
This works as exact match, if you are doing a non-exact match use anchoring:
^[2-9][0-9]*$
if after the initial digit different character can happen use an appropriate pattern e.g:
[2-9].*
matches anything after the first digit:
[2-9][0-9a-zA-Z]*
matches a alfanumeric pattern etc...
If you mean to accept any string that is an integer number bigger than 1:
([1][0-9]+|[2-9][0-9]*)
the first half ([1][0-9]+) will match a number starting by 1 followed by at least another digit, the second will match the numbers 2-9 or a number starting with a digit 2-9 and more figures ([2-9][0-9]*).
Note that this does not accept potentially good integers written with a leading 0, like 0123. If you want to include that as well use:
(0*[1][0-9]+|0*[2-9][0-9]*)
Also note that a pattern like:
(matcher1|matcher2)
is not supported by all RE engines.
I reckon something like this would be useful for you:
(2+)(.)*
It's mean that only words starting with "2" math the expression.
If you wanna try regular expressiona easely, i like the web http://rubular.com/
It has a good interface to test expressions directly onto the web.
Greetings
I am using a RegEx to test if a string is valid. The string must start and end with a number ([0-9]), but can contain comma's within.
I came up with this example, but it fails for strings less than 3 characters (for example 1 or 15 are as valid as 1,8). Presumably this is because I am specifically testing for a first and last character, but I don't know any other way of doing this.
How can I change this RegEx to match my requirements. Thanks.
^[0-9]+[0-9\,]+[0-9]$
Use this:
^[0-9]+(,[0-9])?$
the ,[0-9] part will be optional
visualized:
if you want allow for multiple comma-number groups... then replace the ? with *.
if you want to allow groups of numbers after the comma (which didn't seem to be the case in your example), then you should put + after that number group as well.
if both of the above mentioned are desired, your final regex could look like this:
^[0-9]+(,[0-9]+)*$
^\d+(?:,\d+)*$
should work.
Always have one or more digits at the start, optionally followed by any number of comma-separated other groups of one or more digits.
If you allow commas next to each other, then the second + should be a *, I think.
I would say the regex
\d(,?\d)*
Should satisfy for 1 or more digits that can be separated by only one comma. Note, 1,,2 fails
so basically I want to detect if in these strings:
Hello 123 My 222 dear 112 troll 12 8889
192.1.1.254:10000
the numbers are in a format like this:
[0 to 255][ANYTHING][0 to 255][ANYTHING][0 to 255][ANYTHING][0 to 255][ANYTHING][0 to 65536]
Does anyone know how I can build such a regex?
It is for detecting if anyone posts an IP:Port in unusual format to bypass default ip:port filters.
Edit: As for the first comment: I do not know regex and what I have tried is:
if(regex_match("192.168 najlepszy serwer SAMP!!1 1 join1!! 8080","/^[0-2](*)?[0-5](*)?[0-5](*).(*)[0-2](*)?[0-5](*)?[0-5](*).(*)[0-2](*)?[0-5](*)?[0-5](*).(*)[0-2](*)?[0-5](*)?[0-5](*)?$/"))
{
print("Cannot send message");
}
else
{
print("New message for everyone! :)");
}
and some other not working regexes.
If you don't want to complicate your life checking the exact ranges, the simple regex would be:
/^.*(\d)+.+(\d)+.+(\d)+.+(\d)+.+(\d)+.*$/
The first four (\d)+ parts can be replaced with more complicated check for 0-255 range:
(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)
the last (\d)+ replace with next for port range check:
(6553[0-5]|655[0-2]\d|65[0-4]\d\d|6[0-4]\d\d\d|[1-5]\d\d\d\d|[1-9]\d{0,3})
An exact, simple, and direct representation of your pattern as a regular expression is not possible in the general case. The reason are the number ranges. Something like "at this place any integral number with a value from a to b" is just to complex. A regular expression is executed by a finite state machine and these (theoretical) beasts are (basically) only able to look at strings character by character. Therefore you can match something like "ignore all characters until you find the first digit, then check whether the first digit is followed by at most two more digits".
As a workaround you may try to build a list of alternations of possible digit patterns that covers your desired range of values (in the extreme case list every single value like \b(?:1|2|3|4|...|154|155|...|255)\b). I have a pattern for the range 0-255, but I have none for the range of possible port numbers. So a first approximation may be (really, this is only an approximation and not thoroughly tested):
\b(?:[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])\b.*\b(?:[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])\b.*\b(?:[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])\b.*\b(?:[0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])\b[^0-9]*[0-9]{1,5}
In the above pattern (?: .... ) means a shy group (not remembered for back references) and \b means word boundary.
I'd suggest you read up on Regex syntax. For starters . is special and matches any character. Also doing something like [0-2][0-5][0-5] won't catch something like 192 as 9 is not within 0-5.
According to your requirements here's a Regex that should roughly do what you want
([0-2]?\d{1,2}).*([0-2]?\d{1,2}).*([0-2]?\d{1,2}).*([0-2]?\d{1,2}).*(\d{1,5})?
Each of the ([0-2]?\d{1,2}) portions will match 1 or 2 digits preceded optionally with a 0,1, or 2. Each () will capture a group which you can then examine using a Regex engine. You will need to examine this group as the Regex for each of those portions will match numbers above 255 (specifically 256-299).
The last group (\d{1,5})? is to catch the port number, again you will have to examine this as it will catch any 1 to 5 digit number (hence the {1,5}). The ? makes the group optional, remove it if you want it to have to match against a port number.
As far as doing Regex in C, I haven't had much experience but there should be a way to get all the grouped matches and inspect them. Unfortunately they will be strings so you will have to convert them to integers to examine them.
Are you sure you need regex for this? In my opinion, you do not need regex for this.
Just split numbers into groups which are seperated by non-numeric characters. Then analyze.
What language?
As for actually looking for valid range, take a look at this;
http://www.regular-expressions.info/numericranges.html
I would do this simple regex
((\d|\D)+)*