int() vs .astype('int') Python

.astype() is a method within numpy.ndarray, as well as the Pandas Series class, so can be used to convert vectors, matrices and columns within a DataFrame. However, int() is a pure-Python function that can only be applied to scalar values.

For example, you can do int(3.14), but can't do (2.7).astype('int'), because Python native types don't have any such method. However, numpy.array([1.1, 2.2, 3.3]).astype('int') is valid.

(Strictly, it is also possible to define an __int__() method within one's own classes, which would allow int() to be applied to non-native types. Thanks to @juanpa.arrivillaga for pointing this out.)