c# - Who can help me write a regular expression? -

i find multi-line text beginning of string cc kk end, , must include string c3 , c4, can not include string dd or ee, following test data:

t1 b1 cc c3 c4 z1 t3 dd kk  t4 b2 cc c4 c3 z2 t6 ee kk  t7 b3 cc c3 c4 z3 t9 ff kk  t7 b3 cc c4 c3 z3 t9 ff kk 

expected results , only:

cc c3 c4 z3 t9 ff kk  cc c4 c3 z3 t9 ff kk 

i wrote regular expression(c#), result not expected.

you need make regex engine check condition before matching each single character.

@"(?s)\bcc\b(?:(?!dd|ee).)*?\bkk\b" 

demo

(?:(?!dd|ee).)*? should match character not of dd or ee , 0 or more times (non-greedily). \

update:

(?s)\bcc\b(?:(?!\bdd\b|\bee\b).)*?\bc3\b(?:(?!\bdd\b|\bee\b).)*?\bkk\b