How to mark primes in a List?

Questions
,
1

How to mark special items in a List?
e.g.
Range[5]^2 + 1 = {2, 5, 10, 17, 26}
I want to output {Framed[2], Framed[5], 10, Framed[17], 26} , how to do?

More , how to mark prime vertexs in a Graph plot?

2

Exercise for the interested student: use the following functions to solve this problem…

PrimeQ

Map

If

:wink:

3

Range[5]^2 + 1 /. p_?PrimeQ → Framed[p]

4

If[PrimeQ[#], Style[#, Red], #] & /@ (Range[25]^2 + 1)

NOT be: If[PrimeQ[#], Style[#, Red], #] & /@ Range[25]^2 + 1

5

A similar resolution is to use SetDelay (:>) : Range[10]^2 + 1 /. p_ /; PrimeQ[p] :> Framed[p]. SetDelay gives you more controls. ex. what if the condition is that p-3 is prime then I add frame to p ? You can do:

Range[10]^2 + 1 /. p_ /; PrimeQ[p-3] :> Framed[p]