What is the difference between [1,2,3] and array([1,2,3])

Question

I am learning python and I find a=[1,2,3] is almost the same as a=array([1,2,3]),though the latter will show [1 2 3] when I print it. What is the difference between them?

Answer 1

The first is a Python list and the second is, presumably a numpy array. numpy arrays have drastically different features than lists: lists are easily expanded and contracted 1d vectors of arbitrary Python objects. numpy arrays are memory-compact representations of mostly numbers of arbitrary dimension and fixed size, mainly for use with numerical programming.