How to convert string to integer list?

Saying we have a string:

"1 2 3 4 5 6"

I want to convert this to integer list. First I do:

In[82]:= str = StringReplace["1 2 3 4 5 6", " " -> ","] // List
Out[82]= {"1,2,3,4,5,6"}

No I need to convert Out[82] to be just {1,2,3,4,5,6}.

Any idea? Thanks!

Answer

res = ToExpression@StringSplit["1 2 3 4 5 6", " "]

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

 Head /@ res

{Integer, Integer, Integer, Integer, Integer, Integer}