how to combine intsructions of comparaison in one instruction

i have 4 variables and i want to find whose are similar: example: a=23, b= 3, c=23, d=4, e=23... rather than compare each one: if (a==b), if (a=c)...if (b=a) ...if (c=b)...i would know if there is a way to remplace such instructions with one only instruction thank you

Answer 1

[Azzi Abdelmalek]

idx=ismember([b,c,d,e],a)