How to make an empty list inside a module program? It consatly spews errors [duplicate]

Question

Okay, so, I'm trying to write a program within the module. It goes like this: create empty list, join it with a sample from a certain set called MyList, and then repeat it certain number of times. Sounds simple.

Ex[m_] := Module[
  {sample={}, i = 0},
  While[i < m,
  sample= Join[sample, RandomSample[MyList, 7]];
  i++]
sample
  ]

So, Ex[1], should give me just seven numbers, Ex[2] fourteen, etc. But no. It would be too simple. Ex[1] gives me {10 Null, 12 Null, 31 Null, 2 Null, 38 Null, 17 Null, 7 Null}, and so on. Why? What are those nulls everywhere? Have I definied sample wrong? {} is an empty list, quite obviously. Typing manually

Join[{}, {1, 2, 3, 4, 5, 6, 7}]

Gives me no errors.

Answer 1

when I include the semicolon and the parentheses it seems to work in my Mathematica session like so:

MyList = {1, 2, 3, 4, 5, 6, 7}


Ex[m_] :=  Module[
  {sample = {}, i = 0},
    (While[i < m, 
    sample = Join[sample, RandomSample[MyList, 7]];
    i++];
   sample) 
]

Ex[3]

{5, 1, 4, 3, 7, 2, 6, 4, 3, 2, 1, 7, 6, 5, 6, 1, 2, 7, 5, 4, 3}