numpy array creating with a sequence

Question

I am on my transitional trip from MATLAB to scipy(+numpy)+matplotlib. I keep having issues when implementing some things. I want to create a simple vector array in three dif

Answer 1

Have a look at np.r_. It's basically equivalent to what everyone else has suggested, but if you're coming from matlab, it's a bit more intuitive (and if you're coming from any other language, it's a bit counter-intuitive).

As an example, vector=[0.2,1:60,60.8]; translates to:

vector = np.r_[0.2, 1:61, 60.8]

Answer 2

if I understand the matlab correctly, you could accomplish something like this using:

a=np.array([0.2]+list(range(1,61))+[60.8])

But there's probably a better way...the list(range(1,61)) could just be range(1,61) if you're using python 2.X.

This works by creating 3 lists and then concatenating them using the + operator.

The reason your original attempt didn't work is because

a=[ [0.2], np.linspace(1,60,60), [60.8] ] creates a list of lists -- in other words:

a[0] == [0.2] #another list (length 1)
a[1] == np.linspace(1,60,60) #an array (length 60)
a[2] == [60.8] #another list (length 1)

The array function expects an iterable that is a sequence, or a sequence of sequences that are the same length.

Answer 3

Does arange(0.2,60.8,0.2) do what you want?

http://docs.scipy.org/doc/numpy/reference/generated/numpy.arange.html