How can I create a regex validation expression to allow this string? -


i have regex validation expression (thanks clasg , marvel308):

^((?p\begin{(?\w+)}\s*(?:-?\d+\s*(?:&\s*|\\\n))+\end{\g})|\$\s*(?p>matrix)\s*\$|\$\$\s*(?p>matrix)\s*\$\$|\[\s*(?p>matrix)\s*\]|\(\s*(?p>matrix)\s*\))$

at beginning of each row contain -?\d's allow (but not require) word "\left(". , @ end of each row contain -?\d's allow (but not require) word "\right)" how can edit validation expression satisfy this?

here's regex handles cases:

 (?:(?:\$\$?|\\[$[(]?)\s*|^)\\begin{(\w+)}\s*(?:-?\d+\s*(?:&\s*|\\\\\n))+\\end{\1}\s*(?:\$\$?|\\[]$)]?)?$

see here @ regex101.

edit

here's solution allows matching opening/closing *tags:

^((?p<matrix>\\begin{(?<token>\w+)}\s*(?:-?\d+\s*(?:&\s*|\\\\\n))+\\end{\g<token>})|\$\s*(?p>matrix)\s*\$|\$\$\s*(?p>matrix)\s*\$\$|\\\[\s*(?p>matrix)\s*\\\]|\\\(\s*(?p>matrix)\s*\\\))$

it uses subroutine - matrix - keep bit shorter.

here @ regex101.

here's explanation:

the gut of part of recognizes matrix:

\begin{name} 1 & 2 & 3 \\ 1 & -2 & 4 \\ 1 & 2 & 5 \\ \end{name}

this done part

\\begin{(\w+)}\s*(?:-?\d+\s*(?:&\s*|\\\\\n))+\\end{\1}

which matches backslash followed literal text begin. matches name of matrix inside curly brackets, capturing group one. thereafter matches number of positive or negative numbers (-?\d+) followed either ampersand (&) or 2 backslashes , newline (\\\\\n). these rows may repeat number of times. matches ending backslash , name (captured group 1) inside curly brackets \\end{\1}.

the first version allows (not mandatory) preceded , followed lines consisting of $, $$, \( , \[. no check made enveloping lines match each other.

the second version starts testing naked matrix using gut regex explained above, , doing stores regex subroutine named "matrix" - (?p<matrix>. difference between previous gut regex name of regex stored in named capture group - token. text end of matrix done \\end{\g<token>}) checking literal string inside curly brackets matches part captured group named token.

the test of naked regex followed alternations having allowed surrounding lines correct combinations of characters , using subroutine matrix between them. e.g. alternations

\$\s*(?p>matrix)\s*\$

checks (one) dollar sign, optional white space, actual matrix (by calling subroutine) followed matching terminating line, i.e. single dollar sign.


Comments

Post a Comment

Popular posts from this blog

python - Operations inside variables -

this question has answer here: evaluating mathematical expression in string 12 answers i want make python script finds maximum possible output using 2 operations. problem says there syntax error @ 2nd last line, in b in there. how can fix it? x = 0 = int(input("1st number:")) c = int(input("2nd number:" )) e = int(input("3rd number:" )) in range(4): if == 0: b = "+" elif == 1: b = "-" elif == 2: b = "/" else: b = "*" j in range(4): if j == 0: d = "+" elif j == 1: d = "-" elif j == 2: d = "/" else: d = "*" k = b c d e print(k) if you're after variables e on single line, couldn...
Read more

Generic Map Parameter java -

i having lot of methods of type: public static list<eduusers> getdetails(class c, map<string, integer> params) { list<eduusers> details = null; session session = hibernateutil.getsessionfactory().opensession(); transaction tx = null; try { tx = session.begintransaction(); criteria cr = session.createcriteria(c); (map.entry<string, integer> entry : params.entryset()) { cr.add(restrictions.eq(entry.getkey(), entry.getvalue())); } details = cr.list(); tx.commit(); } catch (exception asd) { log.debug(asd.getmessage()); if (tx != null) { tx.commit(); } } { session.close(); } return details; } i trying have generic method them , have written far: public static <t> list<t> getdetails(class<t> c, class<t> b) { l...
Read more

arrays - What causes a java.lang.ArrayIndexOutOfBoundsException and how do I prevent it? -

what arrayindexoutofboundsexception mean , how rid of it? here code sample triggers exception: string[] name = {"tom", "dick", "harry"}; for(int = 0; i<=name.length; i++) { system.out.print(name[i] +'\n'); } your first port of call should documentation explains reasonably clearly: thrown indicate array has been accessed illegal index. index either negative or greater or equal size of array. so example: int[] array = new int[5]; int boom = array[10]; // throws exception as how avoid it... um, don't that. careful array indexes. one problem people run thinking arrays 1-indexed, e.g. int[] array = new int[5]; // ... populate array here ... (int index = 1; index <= array.length; index++) { system.out.println(array[index]); } that miss out first element (index 0) , throw exception when index 5. valid indexes here 0-4 inclusive. correct, idiomatic for statement here be: for (int index = 0; index <...
Read more