Comprehension

dictcomp
listcomp
setcomp
genexp
Both dict and set use braces {} to initialize comprehension
- The difference on what will be the final result depends on which is provide inside braces
Generation expression does not initialize a list, in that case saves more memory
- Used with tuples and other type of sequences (array.array for example)
- One element is treated per time
On array.array for generation expression you can pass the type of the natural number.
List comprehension are faster than genexp, but can only save the result as List, while genexp can save in any iterable type.