Epigene The task should be reworked. Completing it requires knowledge of anchors, which are not introduced yet. :(
j3sp_1 Totally agree, or knowledge of curly braces (when expecting an exact number of variables).
dshahrocks2 please cn u explain the solution.
ganeshnaidu [deleted]
jimmyshepherd Agreed..don't see how info given in lesson and prior lesson is enough to solve this.
gado_2002 I agree
IggiRex Anchors are not needed to solve this problem. But there's a good point in that some extra knowledge is needed, i solved it once using curly braces and another time using character sets, neither of which has been covered at this point.
catsarenotfood I eventually got the right answer using anchors (^..$), but I tried everyone else's answers in the forum and none of them passed testcase 1 or #6,9,14,15,16.
My theory is that the expected answers are looking for a perfect match, i.e. not having any other characters around it.
rveeblefetzer hey, thanks for teaching me about anchors. you and @brotatoes up above saved me from going crazy.
EDIT: wait, what? Now I don't understand why ^ and $ are not necessary in the next question, Matching Digits & Non-Digit Characters
Racsoth Bah, this is just boring. Neither the previous nor the next challenges needed anchors. We basically need to guess the internal rules of each challenge we try.
Anyway, thank you for the heads up!
ButaFuusen Seconded - no challenge thus far has specified unambiguously whether we should be looking for an exact match or not. This is the first one where anchors have been required.
kasthurisuri53 why we need to add ^ and $.
kasthurisuri53 that for matching same length
rollrodrig You need to use ^ and $ to match the exact same pattern.
quynk94 we use anchor (^) it mean the match string must start with. Example /^a/ will match "a", "ab". It not match "ba".
tpb261 absolutely ridiculous!!
alex_c_freeman I'm attempting to learn RegEx to round out my PHP and JS knowladge, so I'm not in a strong position to critisize. However, the logical answer to the question posed should be
...\....\....\....
to be consistent with the previous question and in general the progression of challenges on HackerRank, and this solution is not accepted. I read the editorial and submitted the authors solution, and it only worked for Python. No suggestions for $ or variations are suggested in this tutorial process, I would suggest rewriting the question, or refrencing what ever other step may be required. Do you agree?
kar_santanu43 You were very close. The correct solution is:
/^...\....\....\....$/
connormmaher Yes but you are using anchors here, his point is that this is literally the second question in the introduction phase of regex and a user shouldn't be expected to utilize anchors prior to them being introduced... This is a horribly written question.
gnemlock As mentioned, you still need anchors to match the exact character count. This works for Python; Java, it mentions the need for a double backslash, so Java would be
^...\\....\\....\\....$
eapmartins .{3}\..{3}\..{3}\..{3}
Looks good.
k_bazaraly why it is not working on javascript?
atif089 Looks like they are looking for an extact string matcfh. At first I was thinking there might be unlimited iterations of
nnn....So to exact match
nnn.nnn.nnn.nnnI used this in JS^(.{3}\.){3}.{3}$
kasthurisuri53 why we need to add ^ and $.
atif089 beginning and end of line
finbel Why doesn't this
.{3}\..{3}\..{3}\..{3}
match this:
`!@.#$%.^&*.()_
?
brotatotes This didn't work for me in python2. Adding (^..$) passed all tests:
^.{3}\..{3}\..{3}\..{3}$
It seems this problem requires an exact matching for the entire string.
k_bazaraly There was some issue with js, support had solved it. Thank you
rveeblefetzer ugh, thank you for this; it helped with python3. Tho, I didn't use the curly braces and 3's, just dots.
nayamama a little improvment.
r'^(.{3}\.){3}.{3}$'kasthurisuri53 [deleted]
bryce_paul_guin1 Otherwise abc.def.def.foo\nfoo" would match
Here's what I did:
three=".{3}" regex_pattern = r"^(?:{three}\.){{3}}{three}$".format(three=three)aarushigarg Thanks. This worked perfectly in python
swojit [deleted]swojit And this?
.{3}(\..{3}){3}
elsonico ".{3}" is actually longer and harder to write compare to "..."
Just saying :)
SaiManideep1 .{3}-->3 to any infinity value
.{3,3}--> should work
nibisha22 Its not working for all test cases
saisaripalli simple solution which is passing for all test cases: "(.{3}\.?){4}".
Overview:
".{3}\." means any character, but not newline, occurs 3 times followed by ".", which occur {0,1}. This whole pattern is grouped and occurs exactly 4 times.
Detail Explanation:
".{3}" .means any character but not a newline occuring 3 times only
"\." In java if you want to match (.) in the test string, you need to escape the dot by using a slash . and \ with another escape character so, \.
"?" Occurs none or at the most one time. Here "\.?" looks for "." occuring exaclty zero or at most one time {0,1}.
"{4}" occurs exactly 4 times. (pattern){4} -pattern ocurs exactly 4 times.
nooba It does not pass test case 1 in JavaScript
w_chou06 Assuming someone is brand new to regex, this is not a great second question in the introductory section. You need to know a lot more then just dot can be any character and to use \. to find dots.
y_heng7 if you failed with
...\....\....\....
try
^...\....\....\....$
^ matches the beginning of the line $ the end of the line
But the problem does not state that we should match the beginning and the end of the line.
littleninja Exactly. Even more annoying: the next problem covers start and end matchers.
aleksaa2 tester.check("(.{3}\\.){3}.{3}");
interstellaridea This Challenge's explaination needs more clarity.
It requires knowledge about the regex engine that is not yet introduced.
For you guys still seeking resources heres what I used to get to the solution
http://rubular.com/
Here is a fantastic youtube video on REGEX. This woman is a badass
https://www.youtube.com/watch?v=EkluES9Rvak
Here my solution that make it through:
regex_pattern = '(^.{3})\.(.{3})\.(.{3})\.(.{3}$)'
twharv0002 That youtube video really is fantastic! Thanks for sharing.
JasonChang The Javascript example seem to be borked. String.prototype.match will return null if there are no matches, which then causes a runtime exception.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/match
JasonChang Updating the code to look like this would be helpful:
function processData(Test_String) { var Array = Test_String.match(Regex_Pattern) || []; console.log("Number of matches :", Array.length); }
Darbicus I just made an override of the match function.
String.prototype.match = function(match) { return function() { return match.apply(this.trim(), arguments) ? match.apply(this.trim(), arguments) : []; } }(String.prototype.match);
ProsperousHeart This is meant to be RegEx only.
Darbicus You should know this question is broken for the Regular Expression to work as they want it. Sure you can rig it to work but if you put my code in you can do it how they are trying to teach you.... or at least you could before I haven't seen it recently. They are assuming RegEx works the same in javascript as it does in other languages. It doesn't.
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