Functions to construct arrays

The usual way to set up an array is via a list. But there are also a couple of convenient methods for generating special arrays, which are given in the following table (Table 4.5):

Methods	Shape	Generates
zeros((n,m))	(n,m)	Matrix filled with zeros
ones((n,m))	(n,m)	Matrix filled with ones
diag(v,k)	(n,n)	(Sub-, super-) diagonal matrix from a vector v
random.rand(n,m)	(n,m)	Matrix filled with uniformly distributed random numbers in (0,1)
arange(n)	(n,)	First n integers
linspace(a,b,n)	(n,)	Vector with n equispaced points between a and b

Table 4.5: Commands to create arrays

These commands may take additional arguments. In particular, the commands zeros, ones, and arange take dtype as an optional argument. The default type is float, except for arange. There are also methods such as zeros_like and ones_like, which are slight variants of the preceding ones. For instance, the zeros_like(A) method is equivalent...